Port 80 and 443 in use when restarting httpd

[NorthwestN]

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE
Parallels Plesk Panel, 10.4.4.29, Linux, x86_64

PROBLEM DESCRIPTION
Sometimes, when httpd is restarted it can't start up again because port 80 is in use. This is all the information I've been able to collect on the process that is using that port.

#  netstat -lp|grep http
tcp        0      0 *:http                      *:*                         LISTEN      29774/
tcp        0      0 *:pcsync-https              *:*                         LISTEN      17432/sw-cp-serverd
tcp        0      0 *:https                     *:*                         LISTEN      29774/
# ps aux|grep 29774
root      5053  0.0  0.0  61224   764 pts/1    S+   08:24   0:00 grep 29774
apache   29774  0.0  0.1  43644 10184 ?        S    May14   0:00 [perl]

Kill -9 will fix the issue (a normal kill -15 won't). The executable [perl] does not give me enough information as to what could be spawning this process and where it is coming from.

Does anyone have any ideas where this process could be coming from or how I can find out?


STEPS TO REPRODUCE
After a time, restart httpd.

ACTUAL RESULT
httpd won't start, port 80 is in use.

EXPECTED RESULT
httpd restarts.

ANY ADDITIONAL INFORMATION

 

[IgorG]

Try to use it - http://kb.parallels.com/en/112020

 

[NorthwestN]

This would only be a work around and does not explain the cause of the issue or how to resolve it.

Thanks for the tip though.