We have two exchange 2007 servers. One is a Microsoft Exchange Edge Transport server in the DMZ the other one is also a MS exchange server installed in the internal network. The firewall is configured to allow ALL ports and protocols from Internal to DMZ and TCP Port 25 from the DMZ situated Edge Transport to the internal mail server.
Everything was working fine, but all the sudden this morning outlook client stopped receiving emails from the Internet. Mails are queuing up in the Edge Transport Server (not able to deliver to the internal mail server). Verified that there were no firewall changes and telnet to port 25 on both email servers were working. But, unfortunately the mails are not being sync'ed from the Edge Transport to Internal Mail server.
Sending email from Outlook client to the Internet do work though.
Due to single mail server, I am urgent asking help from the community. Your assistance are high appreciated.