On Fri, 10 Jul 2020 at 23:36, Job Cacka via mailop <mailop@mailop.org> wrote: > > There is PAT firewall that load balances multiple networks.
Maybe one of those destination networks is unreachable, while others are reachable, so when the load-balancing decision points to the unreachable network, the TCP session will not establish? Have you verified connectivity of each and every backend server from your load-balancers perspective? Using multiple MX records, one for each destination mailserver would be the better setup, as opposed to load-balancing incoming port 25 traffic (probably without appropriate health-checking and logging) of a single MX record. cheers, lukas _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop