These days most of those showing up on this report are spammers sending
mail to your (private) list from a non-existent address. LISTSERV sends a
message back to the phony address stating they are not subscribed and not
allowed to post. Since the address doesn't exist, it bounces back to
LISTSERV.

LISTSERV uses a special Return-Path for each list, that way if it bounces
LISTSERV knows which list it is for. So when these bounce, LISTSERV adds
that non-existent address to that list's error report.

There are different but similar scenarios which causes this, but this is
how it happens.

> In the daily error monitoring report for one of my lists, two of the
> subscribers reported as being monitored don't exist. How and why does that
> happen? Can this be explained at a superficial level?
>
> I noticed because the email addresses were obviously bogus:
>
>  1 09/01 09/01 [log in to unmask]
>                Last error: Domain "RNAGTLTELGT.ORG" doesn't exist.
>
> 1 09/01 09/01 [log in to unmask]
>                Last error: Domain "RNAGTLTELGT.ORG" doesn't exist.
>
> (I don't have access to any more details about this transaction that
> what is listed in the report. At least, not that I know of, or that I know
> how to get.)
>
>
> Christine in Littleton, Massachusetts
>
>