Bv9ARM.ch04.html revision 5b5f4cca7833343cac382387ad86ff573b185d17
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<HTML
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><HEAD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TITLE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Advanced DNS Features</TITLE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><META
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="GENERATOR"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinREL="HOME"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinTITLE="BIND 9 Administrator Reference Manual"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.html"><LINK
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinREL="PREVIOUS"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinTITLE="Name Server Configuration"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch03.html"><LINK
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinREL="NEXT"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinTITLE="The BIND 9 Lightweight Resolver"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch05.html"></HEAD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><BODY
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="chapter"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinBGCOLOR="#FFFFFF"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinTEXT="#000000"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinLINK="#0000FF"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinVLINK="#840084"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinALINK="#0000FF"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="NAVHEADER"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TABLE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinSUMMARY="Header navigation table"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinWIDTH="100%"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinBORDER="0"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCELLPADDING="0"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCELLSPACING="0"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TH
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCOLSPAN="3"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinALIGN="center"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND 9 Administrator Reference Manual</TH
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></TR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinWIDTH="10%"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinALIGN="left"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinVALIGN="bottom"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch03.html"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinACCESSKEY="P"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Prev</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></TD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinWIDTH="80%"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinALIGN="center"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinVALIGN="bottom"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></TD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinWIDTH="10%"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinALIGN="right"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinVALIGN="bottom"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch05.html"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinACCESSKEY="N"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Next</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></TD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></TR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></TABLE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><HR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinALIGN="LEFT"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinWIDTH="100%"></DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="chapter"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="ch04"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Chapter 4. Advanced DNS Features</H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="TOC"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DL
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Table of Contents</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DT
727f5b8846457a33d06f515a10a7e1aa849ddf18Andreas Gustafsson><DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>4.1. <A
8e245ec21beee31a780de9b89ba1e8bb2b9f4c9aAndreas GustafssonHREF="Bv9ARM.ch04.html#notify"
727f5b8846457a33d06f515a10a7e1aa849ddf18Andreas Gustafsson>Notify</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>4.2. <A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceHREF="Bv9ARM.ch04.html#dynamic_update"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Dynamic Update</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><DT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.3. <A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch04.html#incremental_zone_transfers"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Incremental Zone Transfers (IXFR)</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.4. <A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch04.html#AEN767"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Split DNS</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.5. <A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch04.html#tsig"
8e245ec21beee31a780de9b89ba1e8bb2b9f4c9aAndreas Gustafsson>TSIG</A
575e532437cf7f203707765e21767db92fa1e480Mark Andrews></DT
8e245ec21beee31a780de9b89ba1e8bb2b9f4c9aAndreas Gustafsson><DT
8e245ec21beee31a780de9b89ba1e8bb2b9f4c9aAndreas Gustafsson>4.6. <A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceHREF="Bv9ARM.ch04.html#AEN927"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>TKEY</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>4.7. <A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceHREF="Bv9ARM.ch04.html#AEN942"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>SIG(0)</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>4.8. <A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceHREF="Bv9ARM.ch04.html#DNSSEC"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>DNSSEC</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>4.9. <A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceHREF="Bv9ARM.ch04.html#AEN1011"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>IPv6 Support in <ACRONYM
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>BIND</ACRONYM
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> 9</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DL
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce></DIV
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><DIV
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="notify"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.1. Notify</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>DNS</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> NOTIFY is a mechanism that allows master
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinservers to notify their slave servers of changes to a zone's data. In
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinresponse to a <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>NOTIFY</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> from a master server, the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinslave will check to see that its version of the zone is the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeincurrent version and, if not, initiate a zone transfer.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>DNS</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinFor more information about
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>NOTIFY</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>, see the description of the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>notify</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> option in <A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch06.html#boolean_options"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Section 6.2.16.1</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinthe description of the zone option <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>also-notify</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch06.html#zone_transfers"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Section 6.2.16.7</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>. The <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>NOTIFY</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinprotocol is specified in RFC 1996.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="dynamic_update"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.2. Dynamic Update</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Dynamic Update is a method for adding, replacing or deleting
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein records in a master server by sending it a special form of DNS
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein messages. The format and meaning of these messages is specified
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein in RFC 2136.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Dynamic update is enabled on a zone-by-zone basis, by
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein including an <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>allow-update</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>update-policy</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> clause in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>zone</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> statement.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Updating of secure zones (zones using DNSSEC) follows
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein RFC 3007: RRSIG and NSEC records affected by updates are automatically
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein regenerated by the server using an online zone key.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Update authorization is based
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein on transaction signatures and an explicit server policy.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect2"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H2
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect2"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="journal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.2.1. The journal file</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H2
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>All changes made to a zone using dynamic update are stored in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zone's journal file. This file is automatically created by the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein server when when the first dynamic update takes place. The name of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the journal file is formed by appending the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein extension <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.jnl</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> to the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein name of the corresponding zone file. The journal file is in a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein binary format and should not be edited manually.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The server will also occasionally write ("dump")
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the complete contents of the updated zone to its zone file.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This is not done immediately after
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein each dynamic update, because that would be too slow when a large
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zone is updated frequently. Instead, the dump is delayed by
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein up to 15 minutes, allowing additional updates to take place.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>When a server is restarted after a shutdown or crash, it will replay
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the journal file to incorporate into the zone any updates that took
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein place after the last zone dump.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Changes that result from incoming incremental zone transfers are also
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein journalled in a similar way.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The zone files of dynamic zones cannot normally be edited by
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein hand because they are not guaranteed to contain the most recent
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein dynamic changes - those are only in the journal file.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The only way to ensure that the zone file of a dynamic zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is up to date is to run <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>rndc stop</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>If you have to make changes to a dynamic zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein manually, the following procedure will work: Disable dynamic updates
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to the zone using
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>rndc freeze <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="replaceable"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>zone</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This will also remove the zone's <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.jnl</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> file
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and update the master file. Edit the zone file. Run
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>rndc unfreeze <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="replaceable"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>zone</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to reload the changed zone and re-enable dynamic updates.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="incremental_zone_transfers"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.3. Incremental Zone Transfers (IXFR)</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The incremental zone transfer (IXFR) protocol is a way for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinslave servers to transfer only changed data, instead of having to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeintransfer the entire zone. The IXFR protocol is specified in RFC
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein1995. See <A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch09.html#proposed_standards"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Proposed Standards</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>When acting as a master, <ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> 9
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinsupports IXFR for those zones
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinwhere the necessary change history information is available. These
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeininclude master zones maintained by dynamic update and slave zones
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinwhose data was obtained by IXFR. For manually maintained master
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzones, and for slave zones obtained by performing a full zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeintransfer (AXFR), IXFR is supported only if the option
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>ixfr-from-differences</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> is set
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto <KBD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="userinput"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>yes</KBD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>When acting as a slave, <ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> 9 will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinattempt to use IXFR unless
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinit is explicitly disabled. For more information about disabling
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinIXFR, see the description of the <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>request-ixfr</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> clause
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinof the <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>server</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> statement.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="AEN767"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.4. Split DNS</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Setting up different views, or visibility, of the DNS space to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeininternal and external resolvers is usually referred to as a <SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Split
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinDNS</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> setup. There are several reasons an organization
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinwould want to set up its DNS this way.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>One common reason for setting up a DNS system this way is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto hide "internal" DNS information from "external" clients on the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinInternet. There is some debate as to whether or not this is actually useful.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinInternal DNS information leaks out in many ways (via email headers,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinfor example) and most savvy "attackers" can find the information
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinthey need using other means.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Another common reason for setting up a Split DNS system is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto allow internal networks that are behind filters or in RFC 1918
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinspace (reserved IP space, as documented in RFC 1918) to resolve DNS
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinon the Internet. Split DNS can also be used to allow mail from outside
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinback in to the internal network.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Here is an example of a split DNS setup:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Let's say a company named <SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Example, Inc.</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein(<VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>example.com</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinhas several corporate sites that have an internal network with reserved
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinInternet Protocol (IP) space and an external demilitarized zone (DMZ),
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinor "outside" section of a network, that is available to the public.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Example, Inc.</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> wants its internal clients
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto be able to resolve external hostnames and to exchange mail with
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinpeople on the outside. The company also wants its internal resolvers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto have access to certain internal-only zones that are not available
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinat all outside of the internal network.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>In order to accomplish this, the company will set up two sets
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinof name servers. One set will be on the inside network (in the reserved
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinIP space) and the other set will be on bastion hosts, which are "proxy"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinhosts that can talk to both sides of its network, in the DMZ.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The internal servers will be configured to forward all queries,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinexcept queries for <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1.internal</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>, <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.internal</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>, <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinand <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>, to the servers in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinDMZ. These internal servers will have complete sets of information
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinfor <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>, <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>,<SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> </I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1.internal</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinand <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.internal</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>To protect the <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1.internal</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.internal</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> domains,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinthe internal name servers must be configured to disallow all queries
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto these domains from any external hosts, including the bastion
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinhosts.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The external servers, which are on the bastion hosts, will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinbe configured to serve the "public" version of the <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinThis could include things such as the host records for public servers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein(<TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>www.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>ftp.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>),
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinand mail exchange (MX) records (<TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>a.mx.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>b.mx.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>).</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>In addition, the public <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> zones
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinshould have special MX records that contain wildcard (`*') records
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinpointing to the bastion hosts. This is needed because external mail
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinservers do not have any other way of looking up how to deliver mail
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto those internal hosts. With the wildcard records, the mail will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinbe delivered to the bastion host, which can then forward it on to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeininternal hosts.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Here's an example of a wildcard MX record:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="programlisting"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>* IN MX 10 external1.example.com.</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Now that they accept mail on behalf of anything in the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinnetwork, the bastion hosts will need to know how to deliver mail
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto internal hosts. In order for this to work properly, the resolvers on
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinthe bastion hosts will need to be configured to point to the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinname servers for DNS resolution.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Queries for internal hostnames will be answered by the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinservers, and queries for external hostnames will be forwarded back
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinout to the DNS servers on the bastion hosts.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>In order for all this to work properly, internal clients will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinneed to be configured to query <SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>only</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinname servers for DNS queries. This could also be enforced via selective
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinfiltering on the network.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>If everything has been set properly, <SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Example, Inc.</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>'s
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeininternal clients will now be able to:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><UL
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Look up any hostnames in the <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> zones.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Look up any hostnames in the <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1.internal</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.internal</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> domains.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Look up any hostnames on the Internet.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Exchange mail with internal AND external people.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></UL
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Hosts on the Internet will be able to:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><UL
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Look up any hostnames in the <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> zones.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Exchange mail with anyone in the <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site1</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>site2.example.com</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> zones.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></LI
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></UL
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Here is an example configuration for the setup we just
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein described above. Note that this is only configuration information;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for information on how to configure your zone files, see <A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinHREF="Bv9ARM.ch03.html#sample_configuration"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Section 3.1</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Internal DNS server config:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="programlisting"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>&#13;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinacl internals { 172.16.72.0/24; 192.168.1.0/24; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinacl externals { <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="varname"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>bastion-ips-go-here</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinoptions {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forward only;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { // forward to external servers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="varname"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>bastion-ips-go-here</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { none; }; // sample allow-transfer (no one)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; }; // restrict query access
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-recursion { internals; }; // restrict recursion
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzone "site1.example.com" { // sample master zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type master;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file "m/site1.example.com";
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { }; // do normal iterative
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein // resolution (do not forward)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzone "site2.example.com" { // sample slave zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type slave;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file "s/site2.example.com";
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein masters { 172.16.72.3; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzone "site1.internal" {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type master;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file "m/site1.internal";
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; }
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzone "site2.internal" {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type slave;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file "s/site2.internal";
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein masters { 172.16.72.3; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; }
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>External (bastion host) DNS server config:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="programlisting"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>&#13;acl internals { 172.16.72.0/24; 192.168.1.0/24; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinacl externals { bastion-ips-go-here; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinoptions {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { none; }; // sample allow-transfer (no one)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; }; // restrict query access
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-recursion { internals; externals; }; // restrict recursion
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzone "site1.example.com" { // sample slave zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type master;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file "m/site1.foo.com";
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { any; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; externals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinzone "site2.example.com" {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type slave;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file "s/site2.foo.com";
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein masters { another_bastion_host_maybe; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { any; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; externals; }
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>In the <TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="filename"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>resolv.conf</TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> (or equivalent) on
727f5b8846457a33d06f515a10a7e1aa849ddf18Andreas Gustafssonthe bastion host(s):</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce><PRE
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="programlisting"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>&#13;search ...
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinnameserver 172.16.72.2
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinnameserver 172.16.72.3
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinnameserver 172.16.72.4
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein</PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect1"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="tsig"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.5. TSIG</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H1
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>This is a short guide to setting up Transaction SIGnatures
33682c92e96b39c395cdb2c3feb8eb5914e7d5a8Andreas Gustafsson(TSIG) based transaction security in <ACRONYM
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>. It describes changes
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinto the configuration file as well as what changes are required for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeindifferent features, including the process of creating transaction
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinkeys and using transaction signatures with <ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> primarily supports TSIG for server to server communication.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinThis includes zone transfer, notify, and recursive query messages.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinResolvers based on newer versions of <ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="acronym"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>BIND</ACRONYM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> 8 have limited support
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinfor TSIG.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>TSIG might be most useful for dynamic update. A primary
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein server for a dynamic zone should use access control to control
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein updates, but IP-based access control is insufficient.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The cryptographic access control provided by TSIG
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is far superior. The <B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="command"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>nsupdate</B
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein program supports TSIG via the <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="option"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>-k</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="option"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>-y</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> command line options.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect2"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H2
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect2"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="AEN858"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.5.1. Generate Shared Keys for Each Pair of Hosts</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H2
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>A shared secret is generated to be shared between <SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>host1</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein> and <SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="emphasis"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>host2</I
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></SPAN
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinAn arbitrary key name is chosen: "host1-host2.". The key name must
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinbe the same on both hosts.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><DIV
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect3"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><H3
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="sect3"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNAME="AEN863"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>4.5.1.1. Automatic Generation</A
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></H3
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The following command will generate a 128 bit (16 byte) HMAC-MD5
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinkey as described above. Longer keys are better, but shorter keys
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinare easier to read. Note that the maximum key length is 512 bits;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinkeys longer than that will be digested with MD5 to produce a 128
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinbit key.</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><KBD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="userinput"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>dnssec-keygen -a hmac-md5 -b 128 -n HOST host1-host2.</KBD
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein></P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>The key is in the file <TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="filename"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Khost1-host2.+157+00000.private</TT
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinNothing directly uses this file, but the base-64 encoded string
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinfollowing "<VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="literal"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Key:</VAR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeincan be extracted from the file and used as a shared secret:</P
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein><PRE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob AusteinCLASS="programlisting"
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein>Key: La/E5CjG9O+os1jq0a2jdA==</PRE
><P
>The string "<VAR
CLASS="literal"
>La/E5CjG9O+os1jq0a2jdA==</VAR
>" can
be used as the shared secret.</P
></DIV
><DIV
CLASS="sect3"
><H3
CLASS="sect3"
><A
NAME="AEN874"
>4.5.1.2. Manual Generation</A
></H3
><P
>The shared secret is simply a random sequence of bits, encoded
in base-64. Most ASCII strings are valid base-64 strings (assuming
the length is a multiple of 4 and only valid characters are used),
so the shared secret can be manually generated.</P
><P
>Also, a known string can be run through <B
CLASS="command"
>mmencode</B
> or
a similar program to generate base-64 encoded data.</P
></DIV
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN879"
>4.5.2. Copying the Shared Secret to Both Machines</A
></H2
><P
>This is beyond the scope of DNS. A secure transport mechanism
should be used. This could be secure FTP, ssh, telephone, etc.</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN882"
>4.5.3. Informing the Servers of the Key's Existence</A
></H2
><P
>Imagine <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host1</I
></SPAN
> and <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host 2</I
></SPAN
> are
both servers. The following is added to each server's <TT
CLASS="filename"
>named.conf</TT
> file:</P
><PRE
CLASS="programlisting"
>&#13;key host1-host2. {
algorithm hmac-md5;
secret "La/E5CjG9O+os1jq0a2jdA==";
};
</PRE
><P
>The algorithm, hmac-md5, is the only one supported by <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
>.
The secret is the one generated above. Since this is a secret, it
is recommended that either <TT
CLASS="filename"
>named.conf</TT
> be non-world
readable, or the key directive be added to a non-world readable
file that is included by <TT
CLASS="filename"
>named.conf</TT
>.</P
><P
>At this point, the key is recognized. This means that if the
server receives a message signed by this key, it can verify the
signature. If the signature is successfully verified, the
response is signed by the same key.</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN894"
>4.5.4. Instructing the Server to Use the Key</A
></H2
><P
>Since keys are shared between two hosts only, the server must
be told when keys are to be used. The following is added to the <TT
CLASS="filename"
>named.conf</TT
> file
for <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host1</I
></SPAN
>, if the IP address of <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host2</I
></SPAN
> is
10.1.2.3:</P
><PRE
CLASS="programlisting"
>&#13;server 10.1.2.3 {
keys { host1-host2. ;};
};
</PRE
><P
>Multiple keys may be present, but only the first is used.
This directive does not contain any secrets, so it may be in a world-readable
file.</P
><P
>If <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host1</I
></SPAN
> sends a message that is a request
to that address, the message will be signed with the specified key. <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host1</I
></SPAN
> will
expect any responses to signed messages to be signed with the same
key.</P
><P
>A similar statement must be present in <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host2</I
></SPAN
>'s
configuration file (with <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host1</I
></SPAN
>'s address) for <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host2</I
></SPAN
> to
sign request messages to <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>host1</I
></SPAN
>.</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN910"
>4.5.5. TSIG Key Based Access Control</A
></H2
><P
><ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> allows IP addresses and ranges to be specified in ACL
definitions and
<B
CLASS="command"
>allow-{ query | transfer | update }</B
> directives.
This has been extended to allow TSIG keys also. The above key would
be denoted <B
CLASS="command"
>key host1-host2.</B
></P
><P
>An example of an allow-update directive would be:</P
><PRE
CLASS="programlisting"
>&#13;allow-update { key host1-host2. ;};
</PRE
><P
>This allows dynamic updates to succeed only if the request
was signed by a key named
"<B
CLASS="command"
>host1-host2.</B
>".</P
><P
>You may want to read about the more
powerful <B
CLASS="command"
>update-policy</B
> statement in <A
HREF="Bv9ARM.ch06.html#dynamic_update_policies"
>Section 6.2.24.4</A
>.</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN923"
>4.5.6. Errors</A
></H2
><P
>The processing of TSIG signed messages can result in
several errors. If a signed message is sent to a non-TSIG aware
server, a FORMERR will be returned, since the server will not
understand the record. This is a result of misconfiguration,
since the server must be explicitly configured to send a TSIG
signed message to a specific server.</P
><P
>If a TSIG aware server receives a message signed by an
unknown key, the response will be unsigned with the TSIG
extended error code set to BADKEY. If a TSIG aware server
receives a message with a signature that does not validate, the
response will be unsigned with the TSIG extended error code set
to BADSIG. If a TSIG aware server receives a message with a time
outside of the allowed range, the response will be signed with
the TSIG extended error code set to BADTIME, and the time values
will be adjusted so that the response can be successfully
verified. In any of these cases, the message's rcode is set to
NOTAUTH.</P
></DIV
></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="AEN927"
>4.6. TKEY</A
></H1
><P
><B
CLASS="command"
>TKEY</B
> is a mechanism for automatically
generating a shared secret between two hosts. There are several
"modes" of <B
CLASS="command"
>TKEY</B
> that specify how the key is
generated or assigned. <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9
implements only one of these modes,
the Diffie-Hellman key exchange. Both hosts are required to have
a Diffie-Hellman KEY record (although this record is not required
to be present in a zone). The <B
CLASS="command"
>TKEY</B
> process
must use signed messages, signed either by TSIG or SIG(0). The
result of <B
CLASS="command"
>TKEY</B
> is a shared secret that can be
used to sign messages with TSIG. <B
CLASS="command"
>TKEY</B
> can also
be used to delete shared secrets that it had previously
generated.</P
><P
>The <B
CLASS="command"
>TKEY</B
> process is initiated by a client
or server by sending a signed <B
CLASS="command"
>TKEY</B
> query
(including any appropriate KEYs) to a TKEY-aware server. The
server response, if it indicates success, will contain a
<B
CLASS="command"
>TKEY</B
> record and any appropriate keys. After
this exchange, both participants have enough information to
determine the shared secret; the exact process depends on the
<B
CLASS="command"
>TKEY</B
> mode. When using the Diffie-Hellman
<B
CLASS="command"
>TKEY</B
> mode, Diffie-Hellman keys are exchanged,
and the shared secret is derived by both participants.</P
></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="AEN942"
>4.7. SIG(0)</A
></H1
><P
><ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 partially supports DNSSEC SIG(0)
transaction signatures as specified in RFC 2535 and RFC2931. SIG(0)
uses public/private keys to authenticate messages. Access control
is performed in the same manner as TSIG keys; privileges can be
granted or denied based on the key name.</P
><P
>When a SIG(0) signed message is received, it will only be
verified if the key is known and trusted by the server; the server
will not attempt to locate and/or validate the key.</P
><P
>SIG(0) signing of multiple-message TCP streams is not
supported.</P
><P
>The only tool shipped with <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 that
generates SIG(0) signed messages is <B
CLASS="command"
>nsupdate</B
>.</P
></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="DNSSEC"
>4.8. DNSSEC</A
></H1
><P
>Cryptographic authentication of DNS information is possible
through the DNS Security (<SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>DNSSEC-bis</I
></SPAN
>) extensions,
defined in RFC &#60;TBA&#62;. This section describes the creation and use
of DNSSEC signed zones.</P
><P
>In order to set up a DNSSEC secure zone, there are a series
of steps which must be followed. <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 ships
with several tools
that are used in this process, which are explained in more detail
below. In all cases, the <VAR
CLASS="option"
>-h</VAR
> option prints a
full list of parameters. Note that the DNSSEC tools require the
keyset files to be in the working directory or the
directory specified by the <VAR
CLASS="option"
>-h</VAR
> option, and
that the tools shipped with BIND 9.2.x and earlier are not compatible
with the current ones.</P
><P
>There must also be communication with the administrators of
the parent and/or child zone to transmit keys. A zone's security
status must be indicated by the parent zone for a DNSSEC capable
resolver to trust its data. This is done through the presense
or absence of a <VAR
CLASS="literal"
>DS</VAR
> record at the delegation
point.</P
><P
>For other servers to trust data in this zone, they must
either be statically configured with this zone's zone key or the
zone key of another zone above this one in the DNS tree.</P
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN962"
>4.8.1. Generating Keys</A
></H2
><P
>The <B
CLASS="command"
>dnssec-keygen</B
> program is used to
generate keys.</P
><P
>A secure zone must contain one or more zone keys. The
zone keys will sign all other records in the zone, as well as
the zone keys of any secure delegated zones. Zone keys must
have the same name as the zone, a name type of
<B
CLASS="command"
>ZONE</B
>, and must be usable for authentication.
It is recommended that zone keys use a cryptographic algorithm
designated as "mandatory to implement" by the IETF; currently
the only one is RSASHA1.</P
><P
>The following command will generate a 768 bit RSASHA1 key for
the <TT
CLASS="filename"
>child.example</TT
> zone:</P
><P
><KBD
CLASS="userinput"
>dnssec-keygen -a RSASHA1 -b 768 -n ZONE child.example.</KBD
></P
><P
>Two output files will be produced:
<TT
CLASS="filename"
>Kchild.example.+005+12345.key</TT
> and
<TT
CLASS="filename"
>Kchild.example.+005+12345.private</TT
> (where
12345 is an example of a key tag). The key file names contain
the key name (<TT
CLASS="filename"
>child.example.</TT
>), algorithm (3
is DSA, 1 is RSAMD5, 5 is RSASHA1, etc.), and the key tag (12345 in this case).
The private key (in the <TT
CLASS="filename"
>.private</TT
> file) is
used to generate signatures, and the public key (in the
<TT
CLASS="filename"
>.key</TT
> file) is used for signature
verification.</P
><P
>To generate another key with the same properties (but with
a different key tag), repeat the above command.</P
><P
>The public keys should be inserted into the zone file by
including the <TT
CLASS="filename"
>.key</TT
> files using
<B
CLASS="command"
>$INCLUDE</B
> statements.
</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN982"
>4.8.2. Signing the Zone</A
></H2
><P
>The <B
CLASS="command"
>dnssec-signzone</B
> program is used to
sign a zone.</P
><P
>Any <TT
CLASS="filename"
>keyset</TT
> files corresponding
to secure subzones should be present. The zone signer will
generate <VAR
CLASS="literal"
>NSEC</VAR
> and <VAR
CLASS="literal"
>RRSIG</VAR
>
records for the zone, as well as <VAR
CLASS="literal"
>DS</VAR
> for
the child zones if <VAR
CLASS="literal"
>'-d'</VAR
> is specified.
If <VAR
CLASS="literal"
>'-d'</VAR
> is not specified then DS RRsets for
the secure child zones need to be added manually.</P
><P
>The following command signs the zone, assuming it is in a
file called <TT
CLASS="filename"
>zone.child.example</TT
>. By
default, all zone keys which have an available private key are
used to generate signatures.</P
><P
><KBD
CLASS="userinput"
>dnssec-signzone -o child.example zone.child.example</KBD
></P
><P
>One output file is produced:
<TT
CLASS="filename"
>zone.child.example.signed</TT
>. This file
should be referenced by <TT
CLASS="filename"
>named.conf</TT
> as the
input file for the zone.</P
><P
><B
CLASS="command"
>dnssec-signzone</B
> will also produce a
keyset and dsset files and optionally a dlvset file. These
are used to provide the parent zone administators with the
<VAR
CLASS="literal"
>DNSKEYs</VAR
> (or their corresponding <VAR
CLASS="literal"
>DS</VAR
>
records) that are the secure entry point to the zone.</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1004"
>4.8.3. Configuring Servers</A
></H2
><P
>Unlike <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 8,
<ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 does not verify signatures on load,
so zone keys for authoritative zones do not need to be specified
in the configuration file.</P
><P
>The public key for any security root must be present in
the configuration file's <B
CLASS="command"
>trusted-keys</B
>
statement, as described later in this document. </P
></DIV
></DIV
><DIV
CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="AEN1011"
>4.9. IPv6 Support in <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9</A
></H1
><P
><ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 fully supports all currently defined forms of IPv6
name to address and address to name lookups. It will also use
IPv6 addresses to make queries when running on an IPv6 capable
system.</P
><P
>For forward lookups, <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 supports only AAAA
records. The use of A6 records is deprecated by RFC 3363, and the
support for forward lookups in <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 is
removed accordingly.
However, authoritative <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 name servers still
load zone files containing A6 records correctly, answer queries
for A6 records, and accept zone transfer for a zone containing A6
records.</P
><P
>For IPv6 reverse lookups, <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 supports
the traditional "nibble" format used in the
<SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>ip6.arpa</I
></SPAN
> domain, as well as the older, deprecated
<SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>ip6.int</I
></SPAN
> domain.
<ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 formerly
supported the "binary label" (also known as "bitstring") format.
The support of binary labels, however, is now completely removed
according to the changes in RFC 3363.
Any applications in <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 do not understand
the format any more, and will return an error if given.
In particular, an authoritative <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 name
server rejects to load a zone file containing binary labels.</P
><P
>For an overview of the format and structure of IPv6 addresses,
see <A
HREF="Bv9ARM.ch09.html#ipv6addresses"
>Section A.2.1</A
>.</P
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1029"
>4.9.1. Address Lookups Using AAAA Records</A
></H2
><P
>The AAAA record is a parallel to the IPv4 A record. It
specifies the entire address in a single record. For
example,</P
><PRE
CLASS="programlisting"
>&#13;$ORIGIN example.com.
host 3600 IN AAAA 2001:db8::1
</PRE
><P
>It is recommended that IPv4-in-IPv6 mapped addresses not
be used. If a host has an IPv4 address, use an A record, not
a AAAA, with <VAR
CLASS="literal"
>::ffff:192.168.42.1</VAR
> as the
address.</P
></DIV
><DIV
CLASS="sect2"
><H2
CLASS="sect2"
><A
NAME="AEN1035"
>4.9.2. Address to Name Lookups Using Nibble Format</A
></H2
><P
>When looking up an address in nibble format, the address
components are simply reversed, just as in IPv4, and
<VAR
CLASS="literal"
>ip6.arpa.</VAR
> is appended to the resulting name.
For example, the following would provide reverse name lookup for
a host with address
<VAR
CLASS="literal"
>2001:db8::1</VAR
>.</P
><PRE
CLASS="programlisting"
>&#13;$ORIGIN 0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.
1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 14400 IN PTR host.example.com.
</PRE
></DIV
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="Bv9ARM.ch03.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="Bv9ARM.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="Bv9ARM.ch05.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Name Server Configuration</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
>&nbsp;</TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>The <ACRONYM
CLASS="acronym"
>BIND</ACRONYM
> 9 Lightweight Resolver</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>