Missing Session Info, No Logs, and Network Dropouts After Internal Mail Server Test

[Think3108]

Hi everyone,

I'm experiencing a strange issue with my OPNsense firewall after testing an internal mail server, and I'm hoping someone can help shed some light on it.

Here's what's happening:

While the mail server was connected, all devices in the accepted list (which bypass firewall authentication) lost internet access.

As soon as I unplugged the mail server's network cable, those devices immediately regained internet connectivity.

Now, even though all devices are successfully connected and receiving DHCP IPs, and I can see valid ARP entries:

No active session info is being shown for any users in the firewall.

No logs are being generated related to traffic, sessions, or firewall activity.

Additionally, there are brief disconnections (~2–3 seconds) every 2–3 hours across the network.

I've already rebooted the firewall, double-checked the DHCP and firewall rule configs, and everything looks fine—but the session tracking and logging just aren't working.

Could the mail server have introduced a conflict or caused something (like NAT or state table corruption) that's still affecting the firewall?

Any help, suggestions, or troubleshooting tips would be much appreciated!

Thanks in advance!