Modifying the guts of TCP/IP in Mac OS X

[Mark Wieder]

hi-

Here's how to modify the MTU under OSX. There's a lot of
under-the-hood stuff involved, but this article will step you through
it if you *really* need it.

http://docs.info.apple.com/article.html?artnum=107474

There's also a GUI utility call RMAC that automates this for you, but
the documentation is all in Japanese.

http://homepage.mac.com/johanneson/.cv/johanneson/Public/Tweaker.tgz-link.tgz

The pointers above are from

http://www.dslreports.com/faq/allthingsmac/7+Networking#3743

-- 
-Mark Wieder
 mwieder at ahsoftware.net