I'm looking to set up IMAP for people to use outside of work and inside of work. The problem is that I don't want to have them to have to keep changing the server to connect to. Externally they would have to connect to "www.server.com:4566", and internally "server:4566". I have and external adapter "eth0" and an internal adapter "eth1", plus a server running the imap server. I can make the connect from eth0 to the imap server, how do I make the connection bounce from eth1 to the imap server?

I've tried:

iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 4566 -j DNAT --to-destination 192.168.0.249:4566

iptables -t filter -A FORWARD -i eth1 -o eth1 -p tcp -m state --dport 4566 --syn --state NEW,ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -i eth1 -d 192.168.0.249 --dport 4566 -j ACCEPT

The last two not at the same time.

If some has a better idea about how to do it, I'd appreciate it.

TIA

Do you have a local nameserver which is used per dhcp by your clients? Just add 'server' to point to the right IP.

But I don't think that will work. Both of the servers have static IP addresses and our web page is on the internet. It can already find www.server.com. Having 2 addresses point to the web page might confuse things.

I guess I'll have to put it another way. I want IMAP requests to come in eth1, then be forwarded back out eth1 to the IMAP server.

I thought your problem is to connect to your server from either the internet or from an internal net transparently. Looks like I missed your problem.