"Each of the clients are running a server on 56.1.x.4 which needs to have a public IP (e.g. an SSL web server) therefore NAT of any kind cannot be used. " yes it can, you can use a DNAT rule fromt the real external ip to the internal IP. Something like this: iptables -t nat -A PREROUTING -p tcp --dport 8000 -i $EXT_IFACE -j DNAT --to 10.198.0.32:8000 maps port 8000 of the external tcp to internal address 10.198.0.32 port 8000 behind the linux router. Lee W wrote: > Peter Farrow wrote: > >> You might also find this useful.... >> >> http://www.netfilter.org/documentation/HOWTO/NAT-HOWTO-6.html >> >> > > Thanks for all the links, although I don't think they are what I'm after. > > What I'm trying to do is setup something which ( I guess) is something > similar to that which an ISP may have. For example > > ISP External Interface = 55.20.0.2 / 255.255.0.0 > Client 1 external interface = 56.1.1.2 / 255.255.255.0 > Client 2 external interface = 56.1.2.2 / 255.255.255.0 > > > Each of the clients are running a server on 56.1.x.4 which needs to > have a public IP (e.g. an SSL web server) therefore NAT of any kind > cannot be used. > > The ISP central router is responsible for directing the packets at the > correct client router with I guess some form of routing table (but I > haven't got that far in my studyies yet). > > Hope this helps to clarify. > > Regards > > Lee > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos