net.tcp.service smtp check failed, QUIT missing

[Snowpaws]

Hello,

I am new to the forum but have been using Zabbix for years. I am currently using 7.0.0alpha7, although the repository was set to 6.5, for whatever reason. I'm not sure if the problem is with the alpha, so I'm asking the question here.

I am testing SMTP port 25 using the following key: net.tcp.service[smtp,{$SMTP.IP},25]

The server has 2 IPs, but SMTP only on one.
The service is shown as down.

But: If I select "Test" in the item, the result is Up. If I choose "Execute not", it is down:

Capture at the client:

root@deb-foo:~# ngrep -W byline port 25
interface: eth0 (1.2.3.4/255.255.255.255)
filter: ( port 25 ) and ((ip || ip6) || (vlan && (ip || ip6)))
####
T 1.2.3.4:25 -> 5.6.7.8:44546 [AP] #4
220 smtp.foobar.de ESMTP Postfix (Debian/GNU).

##
T 5.6.7.8:44546 -> 1.2.3.4:25 [AP] #6
QUIT.

###
T 1.2.3.4:25 -> 5.6.7.8:44546 [AP] #9
221 2.0.0 Bye.

#######
T 1.2.3.4:25 -> 5.6.7.8:54620 [AP] #16
220 smtp.foobar.de ESMTP Postfix (Debian/GNU).

##^Cexit
18 received, 4 matched

As you can see, the final QUIT ist missing. I am not sure if it a bug in zabbix or in front of the screen. Any ideas?

Environment: Debian 12 bookworm, fully patched



With kind regards, Mario