We have an Exchange server (running on Windows 2003) that we changed the IP address on and moved to a new subnet. It no longer receives external e-mails. It can send just fine and it has no problem accessing internal resources or the internet. But for whatever reason, it will not receive. We didn't make any changes to the external IP nor the ASA firewall rules. I don't even know where to begin troubleshooting on this one. Can anyone help me?