migration revision 8011cb06c90d9b87e241b3efeb8a2eca2b8edddc
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonCopyright (C) 2000 Internet Software Consortium.
816e576f77e2c46df3e3d97d65822aa8aded7c4bDavid LawrenceSee COPYRIGHT in the source root or http://isc.org/copyright.html for terms.
69b641bf31d95fd79a50dcea2cdb0fcb23fe22c6David Lawrence BIND 8 to BIND 9 Migration Notes
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonBIND 9 is designed to be mostly upwards compatible with BIND 8, but
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonthere is still a number of caveats you should be aware of when
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonupgrading an existing BIND 8 installation to use BIND 9.
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson1. Configuration File Compatibility
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson1.1. Unimplemented Options and Changed Defaults
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas GustafssonBIND 9.0.0 supports most, but not all but not of the named.conf
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonoptions of BIND 8. Unimplemented options include those for selective
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson(per-domain) forwarding, sortlists, statistics, and process limits;
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonfor a complete list, see doc/misc/options. We plan to implement most
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonof these in in BIND 9.1.
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas GustafssonIf your named.conf file uses an unimplemented option, named will log a
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonwarning message. A message is also logged about each option whose
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssondefault has changed unless the option is set explicitly in named.conf.
35b61b8fb1f377ec9b68bbc8e4e43fbd2756a04dAndreas Gustafsson1.2. Handling of Configuration File Errors
35b61b8fb1f377ec9b68bbc8e4e43fbd2756a04dAndreas GustafssonIn BIND 9, named refuses to start if it detects an error in
35b61b8fb1f377ec9b68bbc8e4e43fbd2756a04dAndreas Gustafssonnamed.conf. Earlier versions would start despite errors, causing the
35b61b8fb1f377ec9b68bbc8e4e43fbd2756a04dAndreas Gustafssonserver to run with a partial configuration. Errors detected during
35b61b8fb1f377ec9b68bbc8e4e43fbd2756a04dAndreas Gustafssonsubsequent reloads do not cause the server to exit.
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas GustafssonThe set of logging categories in BIND 9 is different from that
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonin BIND 8. If you have customized your logging on a per-category
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonbasis, you need to modify your logging statement to use the
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonnew categories.
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas GustafssonAnother difference is that the "logging" statement only takes effect
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonafter the entire named.conf file has been read. This means that when
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonthe server starts up, any messages about errors in the configuration
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonfile are always logged to the default destination (syslog) when the
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonserver first starts up, regardless of the contents of the "logging"
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonstatement. In BIND 8, the new logging configuration took effect
074ae7bf0993ced96b32e3e85553a401f3f3eca9Andreas Gustafssonimmediately after the "logging" statement was read.
e5dd56553e0e8db9a698bca931a9c9d356792844Andreas Gustafsson1.4. Case sensitivity
95940593a680fd37704b74849902ca7fd2ff8f2aAndreas GustafssonIn BIND 9, ACL names are case sensitive. In BIND 8 they were case
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson2. Zone File Compatibility
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson2.1. Strict RFC1035 Interpretation of TTLs in Zone Files
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonBIND 8 allowed you to omit all TTLs from a zone file, and used the
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonvalue of the SOA MINTTL field as a default for missing TTL values.
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonBIND 9 enforces strict compliance with the RFC1035 and RFC2308 TTL
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonrules. The default TTL is the value specified with the $TTL
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssondirective, or the previous explicit TTL if there is no $TTL directive.
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonIf there is no $TTL directive and the first RR in the file does not
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonhave an explicit TTL field, the error message "no TTL specified" is
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonlogged and loading the zone file fails.
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonTo avoid problems, use a $TTL directive in each zone file.
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson2.2. Periods in SOA Serial Numbers Deprecated
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas GustafssonSome versions of BIND allow SOA serial numbers with an embedded
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonperiod, like "3.002", and convert them into integers in a rather
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonunintuitive way. This feature is not supported by BIND 9; serial
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonnumbers must be integers.
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson2.3. Handling of Unbalanced Quotes
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas GustafssonTXT records with unbalanced quotes, like 'host TXT "foo', were not
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssontreated as errors in some versions of BIND. If your zone files
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssoncontain such records, you will get potentially confusing error
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssonmessages like "unexpected end of file" because BIND 9 will interpret
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafssoneverything up to the next quote character as a literal string.
4e0ab18258915b14c163aa9087390402f5ff599bAndreas Gustafsson2.4. Handling of Line Breaks
4e0ab18258915b14c163aa9087390402f5ff599bAndreas GustafssonSome versions of BIND accept RRs containing line breaks that are not
4e0ab18258915b14c163aa9087390402f5ff599bAndreas Gustafssonproperly quoted with parentheses, like the following SOA:
4e0ab18258915b14c163aa9087390402f5ff599bAndreas Gustafsson ( 1 3600 1800 1814400 3600 )
4e0ab18258915b14c163aa9087390402f5ff599bAndreas GustafssonThis is not legal master file syntax and will be treated as an error
4e0ab18258915b14c163aa9087390402f5ff599bAndreas Gustafssonby BIND 9. The fix is to move the opening parenthesis to the first
8011cb06c90d9b87e241b3efeb8a2eca2b8edddcAndreas Gustafsson2.5. Unimplemented BIND 8 Extensions
8011cb06c90d9b87e241b3efeb8a2eca2b8edddcAndreas GustafssonBIND 8 supports a nonstandard master file directive "$GENERATE" for
8011cb06c90d9b87e241b3efeb8a2eca2b8edddcAndreas Gustafssonautomatically generating multiple instances of certain RRs from a
8011cb06c90d9b87e241b3efeb8a2eca2b8edddcAndreas Gustafssontemplate. This directive is currently unimplemented in BIND 9.
d8417b5f3406f4ace0f3bdb228b05a7b701976d6Andreas Gustafsson3. Interoperability Impact of New Protocol Features
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonBIND 9 uses EDNS0 (RFC2671) to advertise its receive buffer size. It
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonalso sets the AD bit in queries to indicate that it wishes to receive
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonDNSSEC responses (this usage of the AD bit is not yet standard, but
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonhopefully it will be soon).
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonMost older servers that do not support EDNS0 and/or DNSSEC, including
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonall known versions of BIND, will send a FORMERR or NOTIMP response to
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonthese queries. When this happens, BIND 9 will automatically retry the
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonquery without EDNS0 and AD.
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas GustafssonUnfortunately, there exists at least one non-BIND name server
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonimplementation that silently ignores these queries instead of sending
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonan error response. Resolving names in zones where all or most
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssonauthoritative servers use this server will be very slow or fail
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssoncompletely. We have contacted the manufacturer of the name server in
9769d3146777ca71af80b459ecec1ef8e2d05950Andreas Gustafssoncase and are trying to resolve the issue with them.
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafsson4. Unrestricted Character Set
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas GustafssonBIND 9 does not restrict the character set of domain names - it is
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonfully 8-bit clean in accordance with RFC2181 section 11.
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas GustafssonIt is strongly recommended that hostnames published in the DNS follow
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonthe RFC952 rules, but BIND 9 will not enforce this restriction.
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas GustafssonHistorically, some applications have suffered from security flaws
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonwhere data originating from the network, such as names returned by
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssongethostbyaddr(), are used with insufficient checking and may cause a
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonbreach of security when containing unexpected characters; see
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafsson<http://www.cert.org/advisories/CA-96.04.corrupt_info_from_servers.html>
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonfor details. Some earlier versions of BIND attempt to protect these
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonflawed applications from attack by discarding data containing
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssoncharacters deemed inappropriate in host names or mail addresses, under
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonthe control of the "check-names" option in named.conf and/or "options
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonno-check-names" in resolv.conf. BIND 9 provides no such protection;
ecbe731ce428d243b0c7eea5d2d2b24732a698a1Andreas Gustafssonif applications with these flaws are still being used, they should
8011cb06c90d9b87e241b3efeb8a2eca2b8edddcAndreas Gustafsson$Id: migration,v 1.11 2000/09/05 16:51:01 gson Exp $