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<refentry id="systemd-socket-proxyd"

xmlns:xi="http://www.w3.org/2001/XInclude">

<refentryinfo>

<title>systemd-socket-proxyd</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>David</firstname>

<surname>Strauss</surname>

<email>david@davidstrauss.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>systemd-socket-proxyd</refentrytitle>

<manvolnum>8</manvolnum>

</refmeta>

<refnamediv>

<refname>systemd-socket-proxyd</refname>

<refpurpose>Bidirectionally proxy local sockets to another (possibly remote) socket.</refpurpose>

</refnamediv>

<refsynopsisdiv>

<cmdsynopsis>

<command>systemd-socket-proxyd</command>

<arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>

<arg choice="plain"><replaceable>HOST</replaceable>:<replaceable>PORT</replaceable></arg>

</cmdsynopsis>

<cmdsynopsis>

<command>systemd-socket-proxyd</command>

<arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>

<arg choice="plain"><replaceable>UNIX-DOMAIN-SOCKET-PATH</replaceable>

</arg>

</cmdsynopsis>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para>

<command>systemd-socket-proxyd</command> is a generic

socket-activated network socket forwarder proxy daemon for IPv4,

IPv6 and UNIX stream sockets. It may be used to bi-directionally

forward traffic from a local listening socket to a local or remote

destination socket.</para>

<para>One use of this tool is to provide socket activation support

for services that do not natively support socket activation. On

behalf of the service to activate, the proxy inherits the socket

from systemd, accepts each client connection, opens a connection

to a configured server for each client, and then bidirectionally

forwards data between the two.</para>

<para>This utility's behavior is similar to

<citerefentry project='die-net'><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>.

The main differences for <command>systemd-socket-proxyd</command>

are support for socket activation with

<literal>Accept=false</literal> and an event-driven

design that scales better with the number of

connections.</para>

</refsect1>

<refsect1>

<title>Options</title>

<para>The following options are understood:</para>

<variablelist>

<xi:include href="standard-options.xml" xpointer="help" />

<xi:include href="standard-options.xml" xpointer="version" />

</variablelist>

</refsect1>

<refsect1>

<title>Exit status</title>

<para>On success, 0 is returned, a non-zero failure

code otherwise.</para>

</refsect1>

<refsect1>

<title>Examples</title>

<refsect2>

<title>Simple Example</title>

<para>Use two services with a dependency and no namespace

isolation.</para>

<example>

<title>proxy-to-nginx.socket</title>

<programlisting><![CDATA[[Socket]

WantedBy=sockets.target]]></programlisting>

</example>

<example>

<title>proxy-to-nginx.service</title>

<programlisting><![CDATA[[Unit]

ExecStart=]]>&rootlibexecdir;<![CDATA[/systemd-socket-proxyd /tmp/nginx.sock

PrivateNetwork=yes]]></programlisting>

</example>

<example>

<title>nginx.conf</title>

<programlisting>

<![CDATA[[...]

[...]]]>

</programlisting>

</example>

<example>

<title>Enabling the proxy</title>

<programlisting><![CDATA[# systemctl enable proxy-to-nginx.socket

$ curl http://localhost:80/]]></programlisting>

</example>

</refsect2>

<refsect2>

<title>Namespace Example</title>

<para>Similar as above, but runs the socket proxy and the main

service in the same private namespace, assuming that

<filename>nginx.service</filename> has

<varname>PrivateTmp=</varname> and

<varname>PrivateNetwork=</varname> set, too.</para>

<example>

<title>proxy-to-nginx.socket</title>

<programlisting><![CDATA[[Socket]

WantedBy=sockets.target]]></programlisting>

</example>

<example>

<title>proxy-to-nginx.service</title>

<programlisting><![CDATA[[Unit]

ExecStart=]]>&rootlibexecdir;<![CDATA[/systemd-socket-proxyd 127.0.0.1:8080

PrivateNetwork=yes]]></programlisting>

</example>

<example>

<title>nginx.conf</title>

<programlisting><![CDATA[[...]

[...]]]></programlisting>

</example>

<example>

<title>Enabling the proxy</title>

<programlisting><![CDATA[# systemctl enable proxy-to-nginx.socket

$ curl http://localhost:80/]]></programlisting>

</example>

</refsect2>

</refsect1>

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>nginx</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry project='die-net'><refentrytitle>curl</refentrytitle><manvolnum>1</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>