On 2020-07-10 at 14:36 -0700, Job Cacka wrote: > There is PAT firewall that load balances multiple networks. > A Barracuda spam filter > And then the MX server. > > > It was working well until about 6-8 weeks ago when we began to notice > the intermittent issue. > > > Thanks, > Job
I would have a look at that firewall. Is is possible that it may be trying to load balance with a missing host? I see that 50% of the connection attempts, the SYN receives RST,ACK while the other 50% the expected SYN,ACK.¹ For the record, the TTL of the SYN,ACK is two units bigger than the one of the RST,ACK ones. Best regards ¹ not the *same* ones, but of a block of 16, as produced by tcptraceroute, I'm seeing a consistent split of 8/8 _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
