I am seeing some strange TCP behavior on my -current machine.

NetBSD poofball.flame.org 1.4K NetBSD 1.4K (POOFBALL.v6) #0: Wed Sep  8 23:24:56 PDT 1999     explorer@poofball.flame.org:/amd/kechara/raid0/OS/NetBSD/src/sys/arch/i386/compile/POOFBALL.v6 i386

If I do something over ssh, such as "cat /usr/share/misc/termcap" I
will get perhaps 10k before the session locks up.  Sometimes I get
"chunks" after a few seconds, other times I get a total lockup of that
session.

It seems to be related to fragmentation, in that if a packet is
fragmented Bad Things happen.

My setup is a little strange:

NetBSD-current <-> router <-- gre tunnel --> home router <-> NetBSD-1.4

The NetBSD 1.4 box has problems talking to the -current machine.
However, the 1.4 box doesn't have problems talking to another 1.4
machine on the same network as the -current box.

When I turn on path MTU discovery on the -current machine, it seems to
work just fine again, since fragmentation no longer occurs.

--Michael