We're running two enterprise EPiServer installations, each installation serving multiple sites. The sites are load balanced across two web servers. 

We've been using UDP for event replication for a long time now. However, a couple of months ago the two web servers started getting out of sync. So we switched to TCP - which _sort of_ helped. But, from time to time we still experience that the sites are out of sync (changes to exisiting pages are not updated, new/deleted pages are not showing up on the other server, etc).
When enabling TCP I did as shown in this blog: http://andersnordby.wordpress.com/2012/12/18/episerver-remote-events-cms-6-r2/ 

I've tried the EPiServerRemoteEventsListener tool to test if the events are being transferred between the serveres as they should. Which they do, but not always; I may be able to send numerous events back and forth between the servers, and later on (~hours) I may not be able to recieve any events at all.

Could it be a Windows update that may have caused the event replication to suddenly stop working? Any tips are greatly appreciated.