On 1/14/2009 1:52 PM, Randy Klumph wrote:
> All Charter.net subscribers across all our hosted lists are generating
> the following error (only Charter.net is generating this error)
>
> [log in to unmask]
> Last error: 5.1.0 553 5.1.0 tr.wou.edu does not exist
>
> Our Listserv domain is tr.wou.edu which adds to my confusion on the
> error. Ordinarily I would interpret the error to mean the user ID no
> longer exists in Charter.net. However, the addresses are valid and I
> have communicated with the affected users. Charter's response to their
> calls was to deny the problem resides with them .  Since I am woefully
> lacking in email server knowledge, can someone provide some direction
> that I provide Charter to send them on the path to a solution?
>

This error message is indicative of a DNS problem of some sort.  The fact
that only charter.net subscribers seem to be affected indicates that the
problem is probably in the charter.net DNS infrastructure.

The server which rejected the message is apparently configured to validate
the domain portion of the envelope-sender (return-path) address and reject
any message where the sender domain does not resolve in DNS.  This technique
effectively results in the rejection of a great deal of spam and malware with
completely bogus sender addresses, however, it can result in the rejection of
messages from valid domains, if there are DNS problems.

--
Paul Russell, Senior Systems Administrator
OIT Messaging Services Team
University of Notre Dame
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