Router causing massive connection slowdown

[GWabel]

I have a D-Link DI-604 rev. E router, which I use as a firewall for my Sony VAIO desktop running Windows XP Pro SP2.  It's flashed with the latest firmware, and most of the settings are at their defaults (the exceptions being a few opened ports for DCC, and MTU 1490.)  Windows Firewall is off.

Since I last rebooted the router (after changing the MTU,) I've noticed that my Internet speed has been slowly but steadily degrading, and it's now at 50 kilobits per second.  (For comparison, before I installed the router, I was getting around 1 megabit per second.)  Is there a way to improve my performance without regularly rebooting my router?  Thanks.

[ale52]

Sounds like your problem might be that you changed your MTU to a inefficient size.  From Wikipedia on MTU

"Every network has a different MTU, which is set by the network administrator. On Windows 95, you can also set the MTU of your machine. This defines the maximum size of the packets sent from your computer onto the network. Ideally, you want the MTU to be the same as the smallest MTU of all the networks between your machine and a message's final destination. Otherwise, if your messages are larger than one of the intervening MTUs, they will get broken up (fragmented), which slows down transmission speeds. "

You stated that the problem started AFTER you made the change.  Try resetting it back to the original size and see if that makes a difference.

Alan <><  

[GWabel]

Forgot to say, the reason I was at 1490 MTU in the first place was because at 1500 MTU (router default,) some servers wouldn't respond at all.  D-Link's support site suggested lowering the MTU by increments of 10 to resolve the issue, and it worked.

Also, for a little while after I set the MTU to 1490, my speed was fine.  It's only been recently that it got this bad.

[timberwolf]

Have you tried updating the firmware of that router?

http://www.dlink.com/products/support.asp?pid=62&pv=17&sec=0

[GWabel]

I do have version 3.52.

Since I wrote the original post, the issue has changed slightly; my speed is fine now, but I'm constantly (to the tune of once every 1-3 minutes) being dropped from certain IRC servers.  The particular IRC server seems to vary at random, and I'm not having any other connection-related issues; Gaim stays connected, and web browsers work fine.

Also, rebooting isn't solving the problem.