Some of our 70+ subscribers @ED.GOV have been complaining to me that they
are not receiving their daily digest which is "cut" about 11 p.m. (I
believe we are in the same timezone).  Neither we nor they are getting
"bounces" as far as I can see.

Typically, this is symptomatic of either lame DNS delegations or MX hosts
that no longer are able to forward.   Usually *I* will see that bounce
though ... but not in this case.

The system admnistrators at the target domain did not have any
insights.  Thus, I started to do various NSLOOKUPs (actually DiG) and
determined that they have five authoritative DNSes, and five MX
hosts.  The DNSes seemed consistent in NS and MX
structure.  Nevertheless, based upon the tiresome conversation over a
speakerphone (yup, we spent University money on a toll call), I thought
they indicated that they were doing all of the MX processing in their
domain.  Interestingly enough, two of the MX records pointed to
commercial providors.

I decided to try direct mail gatewaying though each of the MX hosts.  The
three within the domain seemed to work, one MX gateway refused connection
(which I also found to be recursively resolvable), the last MX host
accepted the mail and then bounced it back ("we don't relay").

I've sent all of this to the sysadmin at @ED.GOV.

Let's see how he responds?

/Pete Weiss