昨天update了SP2

我是个人使用电信8M全速ADSL用户，外置ADSL Modem 接网卡，使用XP自带PPPoE拨号，外网

使用SP2自带防火墙、BitComet 0.55、eMule 0.43b Build0722(VeryCD)


装SP2前(那时使用NPF防火墙)BT热门下载一般速度是600+KB/s、eMule热门下载速度一般是700+KB/s

装SP2之后BT只有60KB/s左右 、eMule则不到40KB/s……#——$%…………

而且开了BT或eMule后则网页几乎都打不开，若是BT和eMule同开则双双降速到1~2KB/s。。。以前是没这个问题的+_+

问原因及求解决良策(除了叫我关闭防火墙和用其它防火墙外)。

from slashdot

Quote:

One of the changes in SP2 was a rate limiting / queing behavior for the number of current sockets in the SYN/opening state.

In other words, suppose you have an app which tries to open 30 tcp sockets simultaneously. Some of them will get delayed by the OS.

This is to try and thwart the speed of worms or DDoS programs - which very often try and create a zillion tcp connections that never end up connecting.

Unfortuneately, it has the side effect of hurting some p2p apps (like bittorrent) and some web browsing configurations...especially if you've changed the registry value that sets the # of simultaneous socket connections IE will make to the same site. The default is like 3 or 4, but if you upped it to say, 20, and then hit a site that had 30 images all on the same server... it is likely that some of your http requests will get queued until other connect() attempts complete the handshake.

Does it suck that this is affecting some browser and other scenarios ? Yes. The topic is under discussion internally at microsoft.

The _intent_ was to try and slow down the spread of worms/ddos attacks in the event a machine got compromised....a good goal to have i think anyone would agree..

The implementation, however, does have disadvantages

If you decide to try SP2 again, anytime the connecting socket limit is reached, an very specific/obvious event will be logged in the eventlog. If you are experiencing slower network interactive speeds, try looking in the logs to see if you're hitting it.

One mitigation, by the way, is to have a proxy (i.e. squid) on another machine.. that way your handshakes from IE resolve _Very_ fast and your sockets rapidly go from handshake to connected...thus reducing the likelihood of you hitting the queing behavior.