From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Gerritsen" <artur@gmx.net>
Date: Thu, 04 Dec 2003 12:01:51 +0000
Subject: [LARTC] How to route and queue, based on iptables marked packets, at the same time?
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List-Id: <lartc.vger.kernel.org>
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To: lartc@vger.kernel.org

Hi

I want to do some routing an queuing stuff, but I am not sure if this=20
will work.

I have 3 connections on my router:
- eth0 which points to my LAN
- eth1 which point to the Internet over a 2Mbit connection
- eth2/ppp0 which is a DSL connection and points to the Internet, too.

The reason for the two Internet connections is that the 2Mbit connection=20
is fast but expensive, I have to pay the traffic. The DSL connection is=20
flat fee but slow, 384 k/bit up and 64 k/bit downstream.

Both connections do masquerading with their public IPs.

What I want to do is to route some services over the DSL connection, like=20
e-mail traffic. The default route should be the 2Mbit connection.

AFAIK I can't use ip rules to set up routing policies based on the TCP-port=
,=20
so I want to mark the traffic with iptables, to set the routs.=20
My problem is, that I currently use this to prioritise my traffic and to=20
order them into different HTB and SFQ queues.

I found this graphic in the LARTC HOWTO:
        +------------+           +---------+      +-------------+
Packet -| PREROUTING |- routing--| FORWARD |----+-| POSTROUTING |- Packets
input   +------------+  decision +---------+    | +-------------+    out
                           |                    |
                     +-------+                +--------+  =20
                     | INPUT |-Local process -| OUTPUT |
                     +-------+                +--------+


My question is can I mark the packets once in the FORWARD and OUTPUT chain =

to influence the routing decision, and mark them again in the PORSTROUTING =

chain to influence the queuing? Where is the decision how to route?

My routing configuration:
# Routing table for the 2MBit interface
$IP route add "$EXT_2M_NET" dev "$EXT_2M_IF" src "$EXT_2M_IP" table "$EXT_2=
M_RT"
$IP route add default via "$EXT_2M_ROUTER" table "$EXT_2M_RT"
$IP route add "$EXT_2M_NET" dev "$EXT_2M_IF" src "$EXT_2M_IP"

# Routing table for the DSL interface
$IP route add "$EXT_DSL_NET" dev "$EXT_DSL_IF" src "$EXT_DSL_IP" table "$EX=
T_DSL_RT"
$IP route add default via "$EXT_DSL_ROUTE"R table "$EXT_DSL_RT"
$IP route add "$EXT_DSL_NET" dev "$EXT_DSL_IF" src "$EXT_DSL_IP"

# Routing rules
$IP rule add from "$EXT_2M_IP"  table "$EXT_2M_RT"
$IP rule add from "$EXT_DSL_IP" table "$EXT_DSL_RT"

$IP rule add fwmark 10 table "$EXT_2M_RT"
$IP rule add fwmark 20 table "$EXT_DSL_RT"

$IP route add "$INT_NET" dev "$INT_IF" table "$EXT_2M_RT"
$IP route add "$EXT_DSL_NET" dev "$EXT_DSL_IF" table "$EXT_2M_RT"
$IP route add 127.0.0.0/8 dev lo table "$EXT_2M_RT"

$IP route add "$INT_NET" dev "$INT_IF" table "$EXT_DSL_RT"
$IP route add "$EXT_2M_NET" dev "$EXT_2M_IF" table "$EXT_DSL_RT"
$IP route add 127.0.0.0/8 dev lo table "$EXT_DSL_RT"

$IP route add default via "$EXT_2M_IP"

thx,
Jan Gerritsen=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=FF=
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