Had to handle my first support incident from XP SP2's great bug ^H^H^H^H feature that is TCP throttling. Somewhere, MS started listening to Steve Gibson when it comes to security. So they turned off RAW socket support in XP SP2 and added TCP throttling. TCP throtting was added late in the game (I'm pretty sure it was at RC1 or later).

While there's no real reason to do these things, MS claims it adds security, because when a virus runs, it's absolutely impossible for it to use it's own driver or get around “safeguards” like this, right? Sigh... MS usually had well thought out security measures, always keeping in mind if malicious code is running as admin -- it can do anything! At any rate, XP SP2 limits the number of pending TCP connections to 10. Yes, 10.

More than security, it sounds like MS wanted to cripple P2P networks, as a 10 pending connection limit certainly does hurt many implementations. For instance, with eDonkey. I request a file, and get say 300 sources. I'll need to contact each source and get added to the queue. Well, 300 sources * many files = LOTS of connections needed. Since many of the sources could be slow to respond (throw in high latency connections (ever use a satellite?)), or simply offline and timeout, the 10 connection limit gets hit within seconds (I have eMule set to 512 connections max, with 128 per 5 seconds).  Even the defaults are high enough to hit this silly limit.

So today I get a call saying that Outlook won't contact my email server, and after this, the have to reboot their computer to access the Internet. After a bit of chat, I figure out it's XP SP2 being “helpful”, but limiting this guy's network software. The solution? Tell him to google for a hacked TCPIP.sys that gives him unlimited connections. (I'd love to post it here, but I think it'd be a legal issue. Maybe instructions on how to patch your TCPIP.sys file would be OK... At any rate, use google. Also, Neowin had a file in their forums for unlimited connections (other patches increase it to only 50)).

Great job -- forcing average users into downloading cracked system DLLs just to get basic functionality. Oh yea, and not accomplishing anything regarding security either. Fun.