I have two Edge Servers both running EXCH2013 CU5 as well as the Mailbox Server. All running on Windows 2012 R2. Everything is fine with the mail flow until at some point it isn't and there are no errors in the logs. From the edge transport itself I can see all services are running. I can see port 25 is listening on 0.0.0.0 and I can even telnet port 25 but from the outside it's as if it's dead to the world. I even turned off the firewall to see if it was a firewall issue but that's not the case.
If I reboot the server everything could be fine for a few hours or a few days but eventually it just stops receiving. The other edge server picks up everything just fine but eventually it would do the same thing if I wasn't being alerted by a service monitoring my smtp port and let me know that it isn't working so I know at that point I need to reboot the server.
Did anyone else have this issue and fix it?