Question Plesk access log

[BELLUM Labs.]

I noticed that in Plesk httpsd_access_log are written about 4 lines per second with this content:
127.0.0.1 - - [11/May/2017:22:30:20 +0200] "POST /enterprise/control/agent.php HTTP/1.1" 200 853 "-" "-" "-"'/enterprise/control/agent.php' '' '/usr/local/psa/admin/htdocs'
where the number 853 is varying.
Is it normal? What have these lines to do with? The system runs fine.
Many many thanks

 

[IgorG]

I think that it is connections by API RPC to your Plesk server. Maybe your Plesk server is integrated into some kind of billing or automation system?

 

[BELLUM Labs.]

Some extensions are installed, among them Patchman, Watchdog and MagicSpam. Patchman may be the cause...