In this particular case, it  would seem that there is a simple e-mail loop between the two hosts.

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which looks like it involves one of Wil's list-owner (related to -REQUEST) addresses.

If there is inconsistent loop occurring, then that most likely would occur because:

1) he's reconfiguring forwarding 

or

2) references an unsynched DNS (old RRs) which points to the wrong MX

or 

3) more than one MX exists, with different configs, and depending upon precedence availability, occasionally goes to the misconfigured one.

4) could be a problem with his owner address if different from his "everyday" mail address.

I only saw one MX, but I wasn't thorough in my use of NSLOOKUP either.

Additionally, telneting to port 25 for diagnostics purposes was an exercise in [my] futility since the MX host did not "like" where I was coming from (I guess it doesn't "like" spammers; or, those who run anti-spam lists ;-)).

YMMV.

/P

At 16:02 3/19/2005 Saturday, Charles Oriez wrote:
>why would email sent to a list from a properly subscribed address behave like this?  We're seeing this more and more recently.  There was an upgrade a few days before this to v14.3  I dont think we saw this before the upgrade