riddle@woton.UUCP (Prentiss Riddle ) (04/14/88)
I've just installed smail 2.5 on our machine (running SysV without
sendmail) and discovered an interesting pitfall some others might wish
to avoid:
Our UUCP map entry contains some not currently existing hostnames which
we have reserved for future use my marking them DEAD. Sometimes we
find out the hard way that these names collide with unregistered
hostnames in use by someone else. "The hard way" is that someone tries
to send mail to one of these machines, which gets routed through us.
Now that we are running smail and have designated our neighbor and
chief UUCP link as a "smart-host" on which we depend for UUCP routing,
a failed piece of mail like this is not marked as erroneous. Instead
it gets sent to our "smart-host", which looks up the machine name in
its paths file and promptly routes it back to us. Voila! Infinite
mail loop.
I've thought of two solutions for this. The short-term fix is to put
entries in the form "sitename %s" on our own paths file for all of
these not-yet-active links, so that smail will attempt local delivery
(which should fail and bounce the message back to the sender).
The long-term fix, of course, will be to register a domain in the UUCP
Zone and get our own unmistakeable namespace.
-- Prentiss Riddle ("Aprendiz de todo, maestro de nada.")
-- Opinions expressed are not necessarily those of my employer.
-- riddle%woton.uucp@cs.utexas.edu {ihnp4,uunet}!ut-sally!im4u!woton!riddle