Subject: Re: Sendmail pro's :)
From: Mike Tibor (tibor@lib.uaa.alaska.edu)
Date: Sat Mar 02 2002 - 12:59:12 AKST
On Fri, 1 Mar 2002, Craig Callender wrote:
> It's called ETRN, and yes, it is possible. Don't know how though.
That part's relatively easy:
$ telnet mailhost.domain.org 25 ****
Trying 10.0.0.1...
Connected to mailhost.domain.org.
Escape character is '^]'.
220 domain.org ESMTP Postfix
EHLO mydomain.org ****
[ responses snipped ]
ETRN mydomain.org ****
250 Queuing started
quit ****
(the "****" denotes the stuff you type) The above responses are from a
Postfix server, but what you would type (and obviously script later for
normal use) would be the same for Sendmail, or any other worthwhile SMTP
server.
Configuration of the "holding" (sometimes called "store and forward")
server is also simple--give it an MX record at a lower priority than the
endpoint mail server, and lengthen the queuewarn and queuereturn timeouts
to whatever is appropriate given the situation (note that "queuewarn" and
"queuereturn" are sendmail-specific terms). I believe the defaults are
4 hours for queuewarn and 5 days for queuereturn.
Configured this way, other mail servers would attempt to connect to the
endpoint mail server first--if it's reachable, then it's just your typical
SMTP session. If it's not reachable, then the servers deliver to the
"holding" server, which will then periodically attempt delivery to the
endpoint server on its own. Most likely the endpoint server would
establish network connectivity and then immediately run its ETRN script,
causing the holding server to deliver all the queued mail.
Mike
-- Mike Tibor Univ. of Alaska Anchorage (907) 786-1001 voice Network Technician Consortium Library (907) 786-6050 fax tibor@lib.uaa.alaska.edu http://www.lib.uaa.alaska.edu/~tibor/ http://www.lib.uaa.alaska.edu/~tibor/pgpkey for PGP public key
This archive was generated by hypermail 2a23 : Sat Mar 02 2002 - 12:59:14 AKST