Does RFC-879 still have any validity? " HOSTS MUST NOT SEND DATAGRAMS LARGER THAN 576 OCTETS UNLESS THEY HAVE SPECIFIC KNOWLEDGE THAT THE DESTINATION HOST IS PREPARED TO ACCEPT LARGER DATAGRAMS. This is a long established rule. To resolve the ambiguity in the TCP Maximum Segment Size option definition the following rule is established: THE TCP MAXIMUM SEGMENT SIZE IS THE IP MAXIMUM DATAGRAM SIZE MINUS FORTY. The default IP Maximum Datagram Size is 576. The default TCP Maximum Segment Size is 536. "

Michael Dillon <michael@memra.com> writes:

...

I don't think so. They even said in their article that the technical details are based upon this URL http://www.sns-access.com/%7Enetpro/maxmtu.htm and this guy says stuff like:

And, it turns out, depending on how your ISP and other routers encountered on the Internet handle your TCP/IP requests, that a MaxMTU setting of 576, often referred to as the "Internet Standard", will in many cases avoid the fragmentation of packets of data and the slow transfer speeds which result.

He used to be one of my users, at two different ISPs, in fact. I had a long drawn out disagreement about how this was wrong, and mathematically didn't make any sense.

However, lots of people have confirmed that it really does help... which leads me to accept Karl's explanation.

We shouldn't expect anymore from microsoft, really.

Darrell