SMTP Service check failing on zabbix container installation

[dfallin]

i have a few zabbix container instances running, generally ok, but have 2 mail servers (zimbra) that i'm monitoring with net.service(smtp) - and they go to failed state for unknown reason? i can connect to the container and telnet to the mailservers and converse via smtp no problem? in fact, sometimes after i do that, the service will get marked as up again for some time. suggestions?

thx

[Engraf]

May be Zimbra is blocking or greylisting IP from which the incomplete (without RCPT) SMTP session was running? I would look for zabbix ip in the zimbra logs.

[dfallin]

that was my original thought, but notice that i can connect FROM THE CONTAINER! to the ip address and there are no problems? in fact - when i do that, the zabbix condition many times clears up. i'm now seeing this on 2 different zabbix docker installations (2 different networks)