[LARTC] advanced routing for 2 internet lines

[dg1yds@xxxxxx (Dirk Schäpsmeyer)]

Hi all,

I have a Linux box with two connections to the internet over two routers and
a private internal network. The linux box does masquerading.



internet +----------+ 172.16.0.1        +-------------------+
  <----  | Router 1 |-------------------|                   |
	   +----------+                   |  172.16.0.2       |
                                        |                   | eth1
192.168.0.99
                                        |  Linux box
|----------------------- ... clients ...
internet +----------+ 172.16.0.3        |                   |
  <----  | Router 2 |-------------------|  routers on eth0  |
	   +----------+                   |                   |
                                        +-------------------+



Now I want it to work in the way I'll describe now:

Basically, every ip-traffic should work over the default-route 172.16.0.1
(router 1). But ip-traffic with e.g. destination port 8123 und 8124
should work over the 2nd router(172.16.0.3).
Certain webservers, like e.g. gmx.com are should ONLY be connected over
router 2.

To do that, I "invented" following but yet not working solution to it:

      ip route add default via 172.16.0.1 dev eth0
	ip route add default via 172.16.0.3 dev eth0 table 100
	ip rule add fwmark 1 table 100
	ip route flush cache

	iptables -A OUTPUT -t mangle -p tcp -s 172.16.0.2 --dport 8123 -j
MARK --set-mark 1
	iptables -A OUTPUT -t mangle -p tcp -s 172.16.0.2 --dport 8124 -j
MARK --set-mark 1

[..not mentioning masquerading rules etc.. ]

The port routing from 8123 and 8124 over the 2nd router works without
problems.

But how do I create the routing for ftp-traffic and the connecting to
certain webservers over the 2nd router?

Thanks a lot!