Gateway generates wrong IP returns address (4.2, Vax)

[Peter Vanderbilt]

We have a VAX 750 running 4.2 gatewaying between two ethernets.  For some
reason, connections running over the second ethernet have the return
(source) IP address of the first ethernet.  This causes minor problems like
machines on the second net generating arp requests that are not responded
to.  Also the address of the first ethernet happens to end in .255 (class C
host number is all 1's) which some systems don't like (we're planning to
change this).

The code in ip_output.c looks OK which implies that higher level protocols
are (incorrectly) filling in the source IP address.

Has this been seen before?  Is there a known fix?

-- 
Peter Vanderbilt
  arpa:  pv at usc-cse.usc.edu
  csnet: pv at usc-cse
  uucp:  pv at uscvax.uucp or
    ...!{{decvax,ucbvax}!sdcsvax,hplabs,allegra,trwrb}!sdcrdcf!uscvax!pv