I would definately recommend you look at this one....
http://support.microsoft.com/kb/898060
Sounds a bit like the MTU problem I have had recently.
"(E-Mail Removed)" wrote:
> Hello all,
>
> Has someone seen problems with slow dialup networking connections yet?
> I need to get a 2400 baud modem connection running to download files
> from a Windows 2003 server. Everything works fine. I can map drivers,
> I can browse the network but if I start a file copy from the server to
> the client it will stop copying the files after couple of seconds. The
> modem link, PPP and TCP/IP connection is still working fine but on the
> Windows XP machine I will see "The specified network name is no longer
> available". If I do a network trace I will see that the Windows XP
> Client will sent a reset (RST) and terminates the socket connection.
> If I increase the modem speed higher the 2400 baud everything works
> fine.
>
> The client machine is a Windows XP system with SP2 installed and the
> firewall is turned off. The Server is a Windows 2003 system.
>
> Any help is highly appreciated..
>
> Thank you all!!!
>
> Thomas
>