I want to get rid of 4 to 8 hour delays in about 40% of incoming email to
a local office, and believe that proper implementation of ETRN would do it.
Unfortunately the ISP admin is arguing with me about configuration.
The MTA for the domain is a (dialup) Linux host we'll call m1.mydomain.com
using Exim 3.12. The following MX records are for the dialup and the ISP's
queue, respectively:
mydomain.com preference = 10, mail exchanger = m1.mydomain.com
mydomain.com preference = 100, mail exchanger = queue.isp.net
Port 25 is open only to queue.isp.net and internal machines. I'd like the
ISP to reconfigure to eliminate the delays that result from seeing the
local computer in either a disconnected state or unwilling to accept
connections.
The controversial point is whether an MX record is needed for delivery to the
disconnected host if ETRN is involved. I gather from recent discussions
that it
is not, but the RFC isn't convincing. The ISP mail/DNS admin seems to believe
that without the first mx record, or reversed priority (above) all mail would
bounce as there is no local delivery option. It's tough to convince him
otherwise. I'm gathering fodder to hopefully persuade him, otherwise we'll try
to find another ISP or hold the connection open during business hours and
open up port 25 (I'm sorely tempted, but it's not the right solution).
(OT) We have used fetchmail in POP3 mode and all worked well, but somehow
multidrop mode broke recently and hasn't been addressed, hence the switch to
ETRN. Our ETRN requests have met with only a '250' response, with no indication
either during the exchange or by following the mail logs that it's working
at all.
Messages seem to just be delivered by queue runners if the dialup connection
happens to be active.
Thanks in advance for any comments,
jbg
Jeffrey B. Green Personal Computer Consultant - Las Vegas, Nevada
http://jbgreen.com Networking Las Vegas Since 1986
