svn commit: r44835 - head/en_US.ISO8859-1/books/faq
Dru Lavigne
dru at FreeBSD.org
Wed May 14 21:35:25 UTC 2014
Author: dru
Date: Wed May 14 21:35:25 2014
New Revision: 44835
URL: http://svnweb.freebsd.org/changeset/doc/44835
Log:
Remove entry for games through PPP NAT. This has not been true for some time.
Sponsored by: iXsystems
Modified:
head/en_US.ISO8859-1/books/faq/book.xml
Modified: head/en_US.ISO8859-1/books/faq/book.xml
==============================================================================
--- head/en_US.ISO8859-1/books/faq/book.xml Wed May 14 21:23:56 2014 (r44834)
+++ head/en_US.ISO8859-1/books/faq/book.xml Wed May 14 21:35:25 2014 (r44835)
@@ -6425,92 +6425,6 @@ ATDT1234567</programlisting>
</qandaentry>
<qandaentry>
- <question xml:id="ppp-nat-games">
- <para>Why do most games not work with the
- <option>-nat</option> switch?</para>
- </question>
-
- <answer>
- <para>The reason games and the like do not work when
- &man.libalias.3; is in use is that the machine on the
- outside will try to open a connection or send
- (unsolicited) UDP packets to the machine on the inside.
- The NAT software does not know that it should send these
- packets to the interior machine.</para>
-
- <para>To make things work, make sure that the only thing
- running is the software that you are having problems with,
- then either run &man.tcpdump.1; on the &man.tun.4;
- interface of the gateway or enable &man.ppp.8; TCP/IP
- logging (<literal>set log +tcp/ip</literal>) on the
- gateway.</para>
-
- <para>When you start the offending software, you should see
- packets passing through the gateway machine. When
- something comes back from the outside, it will be dropped
- (that is the problem). Note the port number of these
- packets then shut down the offending software. Do this a
- few times to see if the port numbers are consistent. If
- they are, then the following line in the relevant section
- of <filename>/etc/ppp/ppp.conf</filename> will make the
- software functional:</para>
-
- <programlisting>nat port <replaceable>proto</replaceable> <replaceable>internalmachine</replaceable>:<replaceable>port</replaceable> <replaceable>port</replaceable></programlisting>
-
- <para>where <replaceable>proto</replaceable> is either
- <literal>tcp</literal> or <literal>udp</literal>,
- <replaceable>internalmachine</replaceable> is the machine
- that you want the packets to be sent to and
- <replaceable>port</replaceable> is the destination port
- number of the packets.</para>
-
- <para>You will not be able to use the software on other
- machines without changing the above command, and running
- the software on two internal machines at the same time is
- out of the question — after all, the outside world
- is seeing your entire internal network as being just a
- single machine.</para>
-
- <para>If the port numbers are not consistent, there are
- three more options:</para>
-
- <orderedlist>
- <listitem>
- <para>Submit support in &man.libalias.3;. Examples of
- <quote>special cases</quote> can be found in
- <filename>/usr/src/sys/netinet/libalias/alias_*.c</filename>
- (<filename>alias_ftp.c</filename> is a good
- prototype). This usually involves reading certain
- recognized outgoing packets, identifying the
- instruction that tells the outside machine to initiate
- a connection back to the internal machine on a
- specific (random) port and setting up a
- <quote>route</quote> in the alias table so that the
- subsequent packets know where to go.</para>
-
- <para>This is the most difficult solution, but it is the
- best and will make the software work with multiple
- machines.</para>
- </listitem>
-
- <listitem>
- <para>Use a proxy. The application may support
- <literal>socks5</literal> for example, or may have a
- <quote>passive</quote> option that avoids ever
- requesting that the peer open connections back to the
- local machine.</para>
- </listitem>
-
- <listitem>
- <para>Redirect everything to the internal machine using
- <literal>nat addr</literal>. This is the
- sledge-hammer approach.</para>
- </listitem>
- </orderedlist>
- </answer>
- </qandaentry>
-
- <qandaentry>
<question xml:id="fcs-errors">
<para>What are FCS errors?</para>
</question>
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