tonight, i decided to play with setting the MTU on my default route to
the world.  Since I was nearly finished with an FTP of the netbsd-1.0
distribution over a SLIP link, my system's "oh-no" detector went off
the scale and communicated an urgent need to panic to the kernel quite
effectively. :)

If you do a 

  route change -net foo -mtu 1500

(or presumably any other modifier option) with no destination address
specified, the kernel panics, on what looks like a null deref in
ifa_withdstaddr (not too surprising a location, eh?)  it's not obvious
to me where the fix lies and I don't have current sources anywhere at
the moment, so i leave it to you folks.

system specifics: FreeBSD 1.1.5.1 with gnu-ish FPU emulator, latest
iteration of blessed patches, on a 486sx.  Also reproduced on a late
NetBSD 1.0beta binary distribution, GENERICAHA kernel, date
approximately Oct 19th, on a 486dx.  both are on a home ethernet with
a slip router to the rest of the planet.

I'm assuming this problem is likely to be in FreeBSD 2.0, but I don't
know that for sure.

repeat-by:

  root# route change -net 127.0.0.1 -mtu 1500

wont-repeat-by:

  root# route change -net 127.0.0.1 127.0.0.1 -mtu 1500


John Hood					Cthulhu-- just imagine it!
cgull@smoke.marlboro.vt.us