So right now we have our mail server on a VM in ESXi, it's been running great for a long time. This weekend our primary firewall failed us, this hosts our primary & secondary connections. I have a THIRD connection on an entirely different firewall (pfSense), I would love to add a second NIC to our mail server and have it go through that pfSense connection, but I am unsure of how this will work.

Our current mail build is running Redhat Ent 5.9. We have it setup with SplitDNS. The primary subnet is 192.168.127.xxx, this server/connection is mail.ourdomain.com. I want to add a second NIC and put it on the third connection, which is on subnet 192.168.144.xxx and then have that be mail2.ourdomain.com. Handling the external dns and having it point to mail2.ourdomain.com I think is the easy part. I just don't know what I need to do on the zimbra mail server itself. Do I need to add mail2. to our hosts file, anything I need to do to our resolv.conf? SplitDNS? All that....any help you could provide would be GREATLY appreciated. The more detailed the walkthroughs the better lol.

Thanks in adavance.