Hi. I'll do my best to explain what I'm trying to acheive with a linux box and 3 NICS. I have two sets of systems. Each system has about 30 IP addresses spread across various bits of hardware. The two systems are identical (ie have the same 30 IP addresses). The addresses are all part of the class C subnet 192.168.0.* The IP addresses for each system are now set in stone and can't be changed. Furthermore, similar addresses are already in use on our network. I've been given a set of IP addresses I CAN use (172.26.158.*) A diagram might help here ... ----------- ----------------- - System1 ---------|eth1 | ----------- | | | Linux Router | | eth0|------------Rest of the network | | ----------- | | - System2 ---------|eth2 | ----------- ------------------ I also have an address I can use for eth0 which will make the router visible from machines on the rest of the network. This can be set as the default gateway for connections to the 172.26.158.* subnet. I would like PCs on the normal network to be able to connect with either system by addressing them with addresses off the 172.26.158 subnet. I'll assign 30 of these IPs to each system. For example. 172.26.158.10 might be mapped onto 192.168.0.2 on eth1 whilst 172.26.158.50 might be mapped onto 192.168.0.2 on eth2 Is this at all possible? I assume I'll need to use at least DNAT but also apply some other trickery to route to the correct interface. As a newbie to IPTables, I'm not sure how I might even begin to set up rules for this. Hopefully this is the sort of thing people want to do all the time and it will be easy :) Any help would be very much appreciated. Thanks, Al This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify Thales Underwater Systems on +44 1963 370 551. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person.