Strange Networking Problem...port 6667 blocked but I can't find out by what

I'm having a very bizarre networking problem on my machine. This started out while I was trying to troubleshoot some VPN issues I'm having connecting to work, but I believe this may be unrelated.

I tried to use mIRC the other day, and got immediate "connection refused" messages. I thought that was odd since I didn't have anything installed that would prevent access to port 6667.

I tried using telnet to hit port 6667, and immediately got the "Could not open connection to host, on port 6667: Connect failed" message. Again, strange, it should have tried for a second before timing out.

I fired up a process to listen on port 6667, tried telneting to localhost 6667, and was met with the Connect failed message again. It didn't even try.

I got TDIMon from SysInternals, and it shows telnet making the request to get the port and the result is CONNECTION_ABORTED.

Now, the really strange part is, if I boot up in Safe Mode with Networking, I get expected behavior.

Is there some driver causing me problems? How could I go about trying to figure out which one it is? Seems like something is hooked into my TCP/IP stack and doing something very wrong.

Are there any debugging tools for looking at what's been loaded for the networking layers? Maybe see who's got their "hooks" into me?

Thanks,
Patrick

 

Check with your ISP to see if they disable that port.

 

Thanks for the pointers, but I've already ruled that out. This laptop has the company image on it, and others who have the same image don't experience this problem.

I can recreate this problem on any network I plug into, so it's not the ISP. I also ruled that out by creating a process listening on the localhost for port 6667.

I have no firewalls enabled, and the virus scanner is configured by the corporate domain controller, and again, no one else has this problem.

My gut feeling is some network driver or something hooked in to the Networking portion of Windows is getting in my way. It's something I've installed or configured that's different than my co-workers, but I can seem to figure out what.

Patrick

 

I'd be temped to look at your anti-virus software for the cause of the blocking you describe.

However, even if you could connect into your PC on port 6667, that wouldn't fix your problem. 6667 is the port the server listens on. The client port is 6668. Have a look at this.

 

Thankg Reggie, and I'm not worried about 6668 yet. I can't even connect to 6667. Even if I start my own process to listen on 6667 and try to connect to it locally with telnet. It just doesn't work. It wants to feel like anti-virus or firewall issue, but everyone else has the same setup and no problems. I can disable all services and startup items and the problem still occurs.

The only time it goes away is if I boot into Safe Mode. So my guess is some driver, but figuring out which one will be a long exercise.

Patrick

 

My point is access on port 6667 is irrelvant to you. The server uses port 6667. When you connect to mIRC, you connect with a client connection to the server. Normally your client port would be a random port above 1024. With mIRC it appears that a fixed client port is used. So you will connect from your port 6668 to the remote server's port 6667.