Lately I have been having troubles with PMDG aircraft clobbering my simmconnect to other programs. Usually, only on long term flights, about four hours into the flight, my simmconnect fails when I am flying PMDG aircraft. This is only in FSX. I am using a Windows XP, latest version, FSX SP2 and I used the latest versions of FS Commander and FS Flight tracker. When the simconnect fails, the FSC connection pauses, my aircraft begins to stop and pause for several seconds at a time and my FS Clock no longer matches the computer clock. The FS Flight Tracker no longer receives data either, it does not record my touch down or the end of the flight.I have confirmed that no other aircraft cause this trouble than PMDG aircraft.What could possibly be causing this?

Todd,If SimConnect was really failing, the plane itself would not work either. We use SimConnect to talk to the FSX internals the same way as any other addon that uses it.Do you have any sort of security software that's doing real time scans, port blocking etc? That can cause this - SimConnect uses TCP/IP, the same protocol that internet connections use and a lot of these programs see it as an unauthorized TCP/IP connection and interfere with it or block it completely.

I thought it was only the RTM version of Simconnect that used TCP/IP.

I do not believe that I have any security software that would do that. It only happens when I fly pmdg aircraft. The communication between FSX and FSC and FS flight tracker, just stops working. If it were the security software, it would happen with all my aircraft. I fly online with IVAO and the data transmits fine to the network, just not to my external programs. And to really mess things up, it isn't consistent. Sometimes it fails, others it doesn't. Is there some status file that you can look at and find out what is causing the simconnect to fail?

I thought it was only the RTM version of Simconnect that used TCP/IP.

No, it most definitely still does, always has.

I do not believe that I have any security software that would do that. It only happens when I fly pmdg aircraft. The communication between FSX and FSC and FS flight tracker, just stops working. If it were the security software, it would happen with all my aircraft. I fly online with IVAO and the data transmits fine to the network, just not to my external programs. And to really mess things up, it isn't consistent. Sometimes it fails, others it doesn't. Is there some status file that you can look at and find out what is causing the simconnect to fail?

This isn't at all a common problem - any time we've seen issues with SimConnect it's been something actively blocking the TCP/IP connections. We don't guarantee compatibility with other addons - we can't possibly do that, there's far too many out there. I'd try checking with the makers of those programs and see if they have any ideas on what the problem could be.

No, it most definitely still does, always has.

For local applications, on the same PC as FSX, it depends on the client program. If the client is linking to the RTM SimConnect it uses TCP/IP, even if it is in-process. That was changed with SP1 -- pipes were introduced for local and remote clients, and in-process clients are then dealt with directly within process. Pipes over a network are carried by TCP/IP, but locally on the same PC they use memory-mapped file techniques, just like FSUIPC and DDE.So things clobbering the TCP/IP system can clobber SimConnect clients using RTM SimConnect, but hopefully shouldn't clobber others. However, they might because of internal Simconnect maneuverings -- after all the FSX-contained part of SimConnect is the same no matter which version of the DLL is being used.RegardsPete

Pete,When I watch our aircraft being loaded with Sysinternals's TCPView app, I see a bunch of local TCP connections being made - what are these then if it's not SimConnect?