LARTC - Dec 2004 - DHCP Handling and Traffic Control over a Working Load Balanced Dual ISP Setup

I have a working router (thanks to Julian''s patches and the threads on 
this site) load balancing over Dual ISP''s.
Links for the curious (see router setup below as well) -

Necessary Patches - http://www.ssi.bg/~ja/
How to Patch (I use Debian Sarge and downloaded the latest source from 
kernel.org) - http://www.desktop-linux.net/debkernel.htm
Necessary Reading - http://www.ssi.bg/~ja/nano.txt


 A couple of fine tuning issues that are still giving me trouble though --

_Question 1:
_One of my ISP''s hands out IP Addresses dynamically -- has anyone found
a way to handle this elegantly using dhcp client to put the routes 
automatically into the proper routing tables? Currently I just have 
another firewall in front of this interface to do the DHCP requests and 
maintain the dyndns.

_Question 2 :_

Because the second IP address is dynamic I am routing traffic from my 
email server out through the T1 only using an ip src route rule like so:

ip rule add from 192.168.1.6 table 200

Is there a way to handle this traffic just for outgoing smtp using 
fwmark and tc so that other traffic from this server can load balance 
and only outgoing mail is forced over the T-1 line?



_My router config is like this so far and working for the load balancing :_

Currently I configure the main table with a priority of 50 for the main 
table then the following for three special routing tables

ip rule add prio 50 table main
ip ro add 127.0.0.0/8 dev lo scope link


table 200 for the traffic that came in on the static T1 (eth2) :
ip ro add 10.0.0.0/30 dev eth2 src 10.0.0.2 table t1
ip ro add default via 10.0.0.1 table t1
ip rule add prio 200 from 10.0.0.2 table t1
ip route append prohibit default table 200 metric 1 proto static



table 201 for the traffic that came in on the Cable Modem (eth1) :
ip ro add 192.168.111.0/30 dev eth1 src 192.168.111.2 table 201
ip ro add default via 192.168.111.1 table 201
ip rule add prio 201 from 192.168.111.2 table cable
ip route append prohibit default table 201 metric 1 proto static

222 for the default global routes and load balancing:

ip rule add prio 222 table 222
ip route add default table 222 proto static nexthop via 10.0.0.1 dev 
eth2 nexthop via 192.168.111.1 dev eth1


Regards,
Mark Royan