SUMMARY:routing from FDDI to Ethernet

From: mborgarello@server-ito.cv.com
Date: Fri Dec 16 1994 - 05:41:38 CST


I know I'm late, but I was really busy!
My Original question:
==============================================================================
Hello sunners,
I have a problem with routing IP packets between a FDDI network and a normal
ethernet network. The systems on the FDDI are sun w/solaris 2.3 (sic!).
The systems on the ethernet are pc's with lanworkplace.
Between these nets there is a Router which seems to be very well configured.
When the pcs through this router use NFS to the suns, these pc's hang.
We also found where the problem resides, the MTU is different between
ethernet and FDDI AND the dont_fragment flag is set: so We changed the
MTU to 1500 and the problem is solved, BUT the performances on the FDDI have
decreased. In fact the router can't break the packet because the dont_fragment
is set.
The main question is "is it possible (and how) to change the dont_fragment flag"????
I looked in SunSolve and I didn't find what I need (maybe there are too many
items to check !)
TIA
regards
===============================================================================
I received just **ONE** answer. And this is the RIGHT one.
Thanks to Dave HAUT !!
On the solaris machines, issue the following command:

/usr/sbin/ndd -set /dev/ip ip_path_mtu_discovery 0

This will "tell" the solaris machines to not set the "don't fragment" bit in
the fddi packet header. This should fix your problem ...

---------------------------------
  _ /| Dave Haut
  \,o.O' Sr Sys Admin
  =(___)= Level One Communications
     U dhaut@level1.com
             (916) 854-2838



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