multiple isp + nat

Janne Raatikainen
Fri, 13 Jan 2006 11:00:07 -0000

I configured multiple isp (actually only multiple gw) according
http://lartc.org/howto/lartc.rpdb.multiple-links.html.

Now NAT (Internet) seems to work, both external interfaces work ( I
didnt configure load balancing because I dont need it). However I have
problem that I can not ping from NAT to public ip of my  Linux box.
Problem is that I can not connect from 192.168.1.0/24 network to
services listening 84.248.213.195, but I can connect to Internet from
NAT through that interface gateway (84.248.192.0). Connecting with
public ip worked fine when I had simple NAT, with single
Internet-connection.

I also notice that portforwarding from Linux-box (public ip) to computer
under nat doesnt work too. Anyone has idea what is the problem?

# ip rule ls
0:      from all lookup local
32762:  from 84.248.213.195 lookup T1
32764:  from 88.192.38.86 lookup T2
32766:  from all lookup main
32767:  from all lookup default

# ip route
84.248.192.0 dev eth2  scope link  src 84.248.213.195
88.192.32.0 dev eth0  scope link  src 88.192.38.86
192.168.1.0/24 dev eth1  proto kernel  scope link  src 192.168.1.50
88.192.32.0/20 dev eth0  proto kernel  scope link  src 88.192.38.86
84.248.192.0/19 dev eth2  proto kernel  scope link  src 84.248.213.195
default via 88.192.32.1 dev eth0
default via 84.248.192.1 dev eth2

Do I have to use some different kind of iptables-rules (fwmark?), than I used
when I had only one connection to Internet, or do I have to add some
route or gw?

Janne