Weird internet problem - sending large data

Ok, here we go, some specs for you :

Using a NETGEAR DG814, set up to be using PPPoA on a permenant DSL connection to my ISP. Connection works fine, at more than acceptable speeds. Ive got a few port forwarding rules set up, to allow my web server on the network to function, and my UT2004 server to work as well, and msn file sending to work as well.

Now, for some reason, I can't send reletivley large ammounts of data to web pages, for example pictures or particularly long posts (more than 4 paragraphs or so) my MTU is 1500 as suggested, and ive checked all my LAN settigns with DrPing and theyre fine. my RWin is fine, as is everything else. Anyone got any ideas at all?

 

The pages are just timing out... Ive emailed my ISP and they usually get back to me quickly, so hopefully they can work it out.

 

TBH, 1500 is not necessarily an optimal MTU.

Are you certain that is what it should be set at?

 

Thats what my ISP tells me to set it at... so as far as i know its fine.

 

You can test what MTU your network can handle:

Using PING to find the best TCP/IP MTU size

*Note* Have one time tried that my network protocol stack had locked it self to some weird MTU size, so I had to reinstall TCPIP (Though I wouldn't go that way unless you are sure that is the problem)