Hi,
I am having some trouble routing some packets between two dual-homed machines both running iptables.
I have a setup that I assume should be pretty common. I have a LAN (192.168.100.0/24) which has two gateways / firewalls on it. Both the gateways are dual-homed.
My setup is something like so:
LAN ---> (192.168.100.1) Gateway 1 (isp1.global.ip) ---> LAN ---> (192.168.100.2) Gateway 2 (isp2.global.ip) --->
Gateway 1 routes through ISP1 and Gateway 2 through ISP2. Some machines in my LAN have .1 set as the gateway and some have .2 as the gateway.
I have my mail server connected to one of the global IPs that ISP2 has given me. Or in other words, mail server is on the same subnet as the external interface of Gateway 2.
As things are today, packets originating on machines having Gateway 1 as their default gateway traverse out through ISP1, the global internet, back through ISP2 into my global ISP2 subnet. This is a waste of bandwidth as well as slow.
I want to set up a rule on Gateway 1 such that all packets destined to my mail server (actually, my entire ISP2 subnet) should be sent to Gateway 2 for routing.
I tried adding a static route on Gateway 1 to route all packets destined to the mail server to Gateway 2 like so:
route add -host mail.server.ip gw 192.168.100.2
After I set this up, I am able to traceroute to mail server (packets flow through Gateway 2). But when I try connecting to port 25, nothing happens.
1. What is the fastest and easiest way to do what I want? 2. Should I be doing DNAT? 3. Should I be doing something using iptables AND routing?
Your help would be much appreciated.
Thaths -- "Trying is the first step towards failure." -- Homer J. Simpson Slacker Without Borders http://openscroll.org/ Key fingerprint = 8A 84 2E 67 10 9A 64 03 24 38 B6 AB 1B 6E 8C E4
