Today I was trying to get some code running on my home machine (SIP code) when I kept running into problems with respect to registering users and more specifically listening points. My code kept throwing TooManyListeners exceptions. Anyway I was dumbfounded as the exact same code works on multiple other machines. So I thought that some sort of program on my machine was somehow registering itself with my SIP proxy (in desperation!) and ran a netstat to see what was there. Sadly nothing on my port range but I did notice an incredible amount of connections on port 9100?
Initially ignoring this I, later in the day, proceeded to connect to Windows update so that I could upgrade to IE7 (feeling adventurous). The update kept failing to report what updates were available and suggested that I checked my proxy settings. Some would call this a sign not to upgrade but I soldiered on to see what the problem was. Low and behold when I got to my proxy settings I found that somehow my proxy had been set to use a configuration script located at http://localhost:9100/proxy.pac Upon doing a quick search for this I found out that it was the work of Google Web Accelerator and unless you disable the accelerator it will keep overriding the setting no matter how many times you uncheck the box. So that explained all my netstat entries for port 9100, it also fixed my Windows Update problem and allowed me to install IE7 (which I have to say is pretty nice so far). Sadly my SIP problems prevail and it’s not shaping up to be a good weekend 🙁