Many TCP First-Packet-isn't-SYN drops after upgrade to R81.10

[Jonathan]

Hi,

After upgrading from R80.20 to R81.10 we see many many TCP drops in the logs from many servers.

Drops are First Packet Isn't SYN with TCP flags are mostly FIN-ACK, ACK.

No performance or other issue with these servers.

We've never had these drops on R80.20 from these servers, and we haven't changed any topology when upgraded.

I suspect it's just cosmetic or a new logging feature issue, but not sure...

I've noticed a checkbox under Global Properties -> Stateful Inspection -> "Log on drop". I don't know if it was checked before the upgrade, maybe it explains the issue?

One thing to mention, not sure it's related - upgrade is not finished yet, we have one member upgraded and the other one is still running R80.20 but is not functioning (cpstop), so the cluster is actually broken at the moment.

Thanks