250 lines
5.0 KiB
HTML
250 lines
5.0 KiB
HTML
<HTML
|
|
><HEAD
|
|
><TITLE
|
|
>Simple source policy routing</TITLE
|
|
><META
|
|
NAME="GENERATOR"
|
|
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
|
|
REL="HOME"
|
|
TITLE="Linux Advanced Routing & Traffic Control HOWTO"
|
|
HREF="index.html"><LINK
|
|
REL="UP"
|
|
TITLE="Rules - routing policy database"
|
|
HREF="lartc.rpdb.html"><LINK
|
|
REL="PREVIOUS"
|
|
TITLE="Rules - routing policy database"
|
|
HREF="lartc.rpdb.html"><LINK
|
|
REL="NEXT"
|
|
TITLE="Routing for multiple uplinks/providers"
|
|
HREF="lartc.rpdb.multiple-links.html"></HEAD
|
|
><BODY
|
|
CLASS="SECT1"
|
|
BGCOLOR="#FFFFFF"
|
|
TEXT="#000000"
|
|
LINK="#0000FF"
|
|
VLINK="#840084"
|
|
ALINK="#0000FF"
|
|
><DIV
|
|
CLASS="NAVHEADER"
|
|
><TABLE
|
|
SUMMARY="Header navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TH
|
|
COLSPAN="3"
|
|
ALIGN="center"
|
|
>Linux Advanced Routing & Traffic Control HOWTO</TH
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="left"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="lartc.rpdb.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="80%"
|
|
ALIGN="center"
|
|
VALIGN="bottom"
|
|
>Chapter 4. Rules - routing policy database</TD
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="right"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="lartc.rpdb.multiple-links.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><H1
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="LARTC.RPDB.SIMPLE"
|
|
></A
|
|
>4.1. Simple source policy routing</H1
|
|
><P
|
|
>Let's take a real example once again, I have 2 (actually 3, about time I
|
|
returned them) cable modems, connected to a Linux NAT ('masquerading')
|
|
router. People living here pay me to use the Internet. Suppose one of my
|
|
house mates only visits hotmail and wants to pay less. This is fine with me,
|
|
but they'll end up using the low-end cable modem.</P
|
|
><P
|
|
>The 'fast' cable modem is known as 212.64.94.251 and is a PPP link to
|
|
212.64.94.1. The 'slow' cable modem is known by various ip addresses,
|
|
212.64.78.148 in this example and is a link to 195.96.98.253.</P
|
|
><P
|
|
>The local table:</P
|
|
><TABLE
|
|
BORDER="1"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="SCREEN"
|
|
>[ahu@home ahu]$ ip route list table local
|
|
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
|
|
local 10.0.0.1 dev eth0 proto kernel scope host src 10.0.0.1
|
|
broadcast 10.0.0.0 dev eth0 proto kernel scope link src 10.0.0.1
|
|
local 212.64.94.251 dev ppp0 proto kernel scope host src 212.64.94.251
|
|
broadcast 10.255.255.255 dev eth0 proto kernel scope link src 10.0.0.1
|
|
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
|
|
local 212.64.78.148 dev ppp2 proto kernel scope host src 212.64.78.148
|
|
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
|
|
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1 </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
>Lots of obvious things, but things that need to be specified somewhere.
|
|
Well, here they are. The default table is empty.</P
|
|
><P
|
|
>Let's view the 'main' table:</P
|
|
><TABLE
|
|
BORDER="1"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="SCREEN"
|
|
>[ahu@home ahu]$ ip route list table main
|
|
195.96.98.253 dev ppp2 proto kernel scope link src 212.64.78.148
|
|
212.64.94.1 dev ppp0 proto kernel scope link src 212.64.94.251
|
|
10.0.0.0/8 dev eth0 proto kernel scope link src 10.0.0.1
|
|
127.0.0.0/8 dev lo scope link
|
|
default via 212.64.94.1 dev ppp0 </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
>We now generate a new rule which we call 'John', for our hypothetical
|
|
house mate. Although we can work with pure numbers, it's far easier if we add
|
|
our tables to /etc/iproute2/rt_tables.</P
|
|
><TABLE
|
|
BORDER="1"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="SCREEN"
|
|
># echo 200 John >> /etc/iproute2/rt_tables
|
|
# ip rule add from 10.0.0.10 table John
|
|
# ip rule ls
|
|
0: from all lookup local
|
|
32765: from 10.0.0.10 lookup John
|
|
32766: from all lookup main
|
|
32767: from all lookup default</PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
>Now all that is left is to generate John's table, and flush the route cache:</P
|
|
><TABLE
|
|
BORDER="1"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="SCREEN"
|
|
># ip route add default via 195.96.98.253 dev ppp2 table John
|
|
# ip route flush cache</PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
>And we are done. It is left as an exercise for the reader to implement this
|
|
in ip-up.</P
|
|
></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="lartc.rpdb.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="index.html"
|
|
ACCESSKEY="H"
|
|
>Home</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="lartc.rpdb.multiple-links.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
>Rules - routing policy database</TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="lartc.rpdb.html"
|
|
ACCESSKEY="U"
|
|
>Up</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
>Routing for multiple uplinks/providers</TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
></BODY
|
|
></HTML
|
|
> |