Hi,
We have been running Untangle / Exchange (Win Server 2008) for several years. Over the past 3 weeks, a weird issue has surfaced.
All works perfectly for around (but not exactly) 24 hours. Then incoming emails from external sources stop. We can receive internal emails and can send emails both internally and externally. Untangle seems fine, plenty of system resources, and all web pages display fine.
Now, here's the weird bit. If we restart Untangle server by itself it does not solve the issue. If we restart the Exchange server by itself it also does not solve the issue. But if we restart both at the same time, it always starts the flow of incoming emails to our users (20 users). All will be fine for the next 24 or so hours, then we'll have to reboot both again.
I didn't see anything obvious in the Exchange event logs. Any idea where I should start looking ?
Apologies, I just tried to upload our topology diagram but the forum isn't allowing me to upload images. BTW, I know it's not recommended, but our Active Directory / DHCP server also runs our exchange, but this has not been an issue in the past.
Thanks in advance