connect/disconnect from localhost.localhost[127.0.0.1] in maillog every 30s

[Guest]

[brawoens]

After upgrading my endian machine yesterday, I see the following lines coming into the /var/log/maillog about every 32 seconds.

Aug 29 12:37:13 endian postfix/smtpd[25322]: connect from localhost.localhost[127.0.0.1]
Aug 29 12:37:13 endian postfix/smtpd[25322]: disconnect from localhost.localhost[127.0.0.1]
Aug 29 12:37:45 endian postfix/smtpd[26415]: connect from localhost.localhost[127.0.0.1]
Aug 29 12:37:45 endian postfix/smtpd[26415]: disconnect from localhost.localhost[127.0.0.1]
Aug 29 12:38:17 endian postfix/smtpd[25322]: connect from localhost.localhost[127.0.0.1]
Aug 29 12:38:17 endian postfix/smtpd[25322]: disconnect from localhost.localhost[127.0.0.1]
Aug 29 12:38:49 endian postfix/smtpd[26415]: connect from localhost.localhost[127.0.0.1]
Aug 29 12:38:49 endian postfix/smtpd[26415]: disconnect from localhost.localhost[127.0.0.1]

I didn't see those in my previous version.
The main.cf en master.cf of postfix haven't changed.
I know this by comparing the current file and the .old file the upgrader tool creates.

The upgrade has been by efw-upgrade.
Current version:
cat /etc/release
Endian Firewall Community release 2.4.0

It seems to me some new process is connecting to the mailserver every 30 seconds.
I think it is not doing harm, but is flooding/dirtying my logs.
Has anyone seen this as well and know what the culprit is?

Thanks in advance.

 Ben

[brawoens]

Here is some extra info.
When I change the inet_interfaces = all to only the eth0 ip in /etc/postfix/main.cf and restart postfix, I dont see the lines anymore, but there is a restart of postfix every 30s.
I figure there must be some kind of monitor process which checks if postfix is up.

Is this endian monitoring or postfix itself which monitors?

I haven't been able to find the process so far.
Tried with:
while true; do fuser smtp/tcp ; done
The process doesn't come up here however, I think it must be too short when it connects.
Has anyone an idea to find out which is the connecting process?

Thanks.