sendmail: expansion too long

[Clifford B Miller]

Here's something odd:

On several IRIS's that were working just fine, suddenly within the past
week we get complaints from users that they can't send mail.  The diagnostic:
"cliff at research.nec.com: rewrite: expansion too long"
and /usr/lib/sendmail -bt gives
@research.nec.com: @research.nec.com: @research.nec.com:... [ad infinitum]...
cliff at research.nec.com

We haven't touched sendmail, or the name server, or YP, or anything else
as far as we know.  Why does this suddenly appear out of nowhere?
And how does one permanently fix it?
--cliff at research.nec.com
OR, if the mailer bounces it back (!)
--millercb at phoenix.princeton.edu