We've got a couple of servers with external IP addresses NAT'd to internal IP addresses. Unfortunately the firewall that's performing the NAT isn't under our control and we have a problem where the servers can't access each other via their external IPs. This causes a problem when we use domain names on the servers, as the DNS lookup returns the external IP address. Ideally I'd like to avoid maintaing hosts files or an internal DNS server. I looked to solve this with a iptables rule on each of the servers as follows: iptables -t mangle -A PREROUTING -d 1.1.1.32/29 -j NETMAP --to 2.2.2.32/29 where 1.1.1.32/29 is the range of external IPs and 2.2.2.32/29 is the range of internal IPs. I was expecting this to map the IP address from the external to the internal IP. Firstly, I'm not sure if this would work at all, and if I'm heading in completely the wrong direction and someone has a better solution, I'd be happy to hear it. Secondly, if I've got the right idea my implementation is a little wrong. When I run the command, I get "iptables: Invalid argument", which doesn't provide much info, and I'm not sure how to go about debugging. A little system info: nick@blade6-dev1:~$ uname -a Linux blade6-dev1 2.6.26-2-amd64 #1 SMP Thu Nov 5 02:23:12 UTC 2009 x86_64 GNU/Linux nick@blade6-dev1:~$ sudo iptables -V iptables v1.4.2 Any thoughts greatly appreciated. Thanks Nick -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
