Mail return address problem

[cqny at vax5.cit.cornell.edu]

I've been having an ongoing problem with mail message return addresses:

Mail originates on VAX/VMS, sent through Ultrix DECnet/Internet gateway, to
an internet address.  The message is sent, but the return address
on the message looks like:
From: user%vmshost.dnet at ultrixhost

This works fine with 'local' internet addresses, but distant recipients
often complain that the return address lacks the fully-qualified domain
name for the ultrixhost, i.e.:
From: user%vmshost.dnet at ultrixhost.domain.cornell.edu

Has anyone fixed this problem; I find the rules in sendmail.cf rather opaque.
Please mail replies to marisa at cpa.tn.cornell.edu

thanx, -- Rich Marisa
Cornell Programmable Automation
(607) 255-7636