Fresh Centos 7 box - SMTP Down! But its not!

[deunan]

Hello all

I have a newly deployed Centos 7 Box, I installed the agent from Zabbix's repo, enable it..

All other triggers enabled are fine, except for the SMTP.

Immediately I received a PROBLEM email saying the SMTP is down. Itis not down! I ran the zabbix_get on Zabbix Server and got thus -

# zabbix_get -s newbox -k net.tcp.service[smtp]
1

Logs on both agent and server are strangely undemonstrative.

Appreciate it very much if anyone can shed some light on this.

[guzzijason]

Do you have firewalld enabled on the CentOS 7 host? If so, it only permits connections for SSH and dhcpv6-client by default. Anything else would need to be added to the firewalld rules.

__Jason

[deunan]

Hello Jason

Thank you for your reply.

You're right on the firewalld. The problem was - a freshly installed Centos box has its SMTP Daemon running, listening only on localhost - 127.0.0.1

Zabbix SMTP Template requires SMTP should also be listening on its forward facing interface - thus - it detects it as down.

So, its either having postfix's main.cf "inet_interfaces = all" and allowing the traffic via firewallD or (I haven't tried this yet) changing the Zabbix rule to net.tcp.listen[25]

Regards