We have a script for troubleshooting in misc/debug folder (in SVN only).
If for example use it (for integration with 3rd applications etc) to get queue on a zabbix server you will see that in command line in random cases a result returned is empty or looks like a line wrap.
If turn on debug log for trappers and capture traffic by wiresharc it get's clear that a ZBXDx01XXXXXXXX header for request is fragmented and on edge cases it became a problem.
For example after 2 PSH packets received from the script (ZBXBx01 and x65) - zabbix trapper closes connections by sending FIN packet.
In debug log we can see:
But sometimes the header is split to 5 PSH packets (data in 6th PSH packet) and it was successfully
proceed by zabbix trapper.
I guess we should improve the script to perform only one push after constructing the header.
Queue protocol is here http://zabbix.org/wiki/Docs/protocols/queue/2.2
Debug log of a successful request:
Mentioned 2 session captures can be seen on a screenshot.