Re: 2.99.50s19 smtp & hotmail.com

["David S. Miller" <davem@redhat.com>]

   From: Matti Aarnio <mea@nic.funet.fi>
   Date: 	Fri, 2 Jul 1999 21:56:38 +0300 (EET DST)

	   No, although I have also encountered these hotmail.com
	   jams.

	   In the CVS there are some attempts at solving it.  To a
	   large extent I gave up at figuring it out, and made a
	   kludge into the scheduler to burst the "log-jamm" by
	   closing the stuck transport agent after 1 hour delay at the
	   FeedAge meter when the OverFed count is 0.

Just a note, hotmail uses a funny rate limiting device in front of
their machines which directly messes with TCP header contents and does
other nasty things.

This appliance has bugs, and Linux was able to trigger it, the most
problematic seems to be TCP timestamps.  The appliance aparently has
some bug workaround for BSDi which occaisionally sets the packet
length wrong when timestamps are used, the appliance "adjusts" the
packet length to try to fix the bug in BSDi.  It seems to break
connections to clients who do TCP timestamps correctly.

Later,
David S. Miller
davem@redhat.com