[comp.mail.sendmail] Second shot after TCP fails?

jeffrey@ccnysci.UUCP (Jeffrey L Bromberger) (06/24/89)

Here's an interesting question.  Let's say I send mail to
user@foo.bar.com, and sendmail's rulesets decide that this should go 
via SMTP.  The mailer tries to resolve the name foo.bar.com by 
talking to the appropriate nameservers on the network, but finds out 
that foo.bar.com is not a "fully qualified domain name" by network 
standards.  Is sendmail bright enough to try the UUCP approach (send 
the name off to smail for resolution) after the SMTP connection fails?  
By fails, I mean that there's no Internet number for the host, and not
that the connection was refused due to a high load average.  Maybe 
sendmail _can_ do this, but it's dependent on how the .cf file 
was created?  Any help would be greatly appreciated.
-- 
Jeffrey L. Bromberger
System Operator---City College of New York---Science Computing Facility
Anywhere!{cmcl2,philabs,phri}!ccnysci!jeffrey	jeffrey@ccnysci.BITNET

steve@eleazar.dartmouth.edu (Steve Campbell) (06/27/89)

In article <2313@ccnysci.UUCP> jeffrey@ccnysci.UUCP (Jeffrey L Bromberger) writes:
>...Let's say I send mail to
>user@foo.bar.com, and sendmail's rulesets decide that this should go 
>via SMTP.  The mailer tries to resolve the name foo.bar.com by 
>talking to the appropriate nameservers on the network, but finds out 
>that foo.bar.com is not a "fully qualified domain name" by network 
>standards.  Is sendmail bright enough to try the UUCP approach (send 
>the name off to smail for resolution) after the SMTP connection fails?  

No.  Once ruleset zero resolves to a particular mailer - the TCP mailer
in your example - then there is no turning back.  If that mailer comes
up with a fatal error such as unknown host, then the message bounces.

While this may be a shortcoming in some instances, the particular situation
described here "should not happen."  This is because if foo.bar.com is
a legitimate, registered domain name, then there should be a mail forwarder
for it on the Internet as well as a name server on the Internet to put
forth MX records pointing to the forwarder.  This should be true even if
foo.bar.com is a UUCP-only site with no Internet connections.  If all this
is not the case, then people shouldn't be using foo.bar.com in email.

							Steve Campbell
							Dartmouth College