Here's an interesting "bounce" message from LISTSERV ...
+++
| 1 10/09 10/09 User Name <[log in to unmask]>
|               Last error: 553 <[log in to unmask]>... Mail from 142.104.5.230
|                           refused; see http://www.dorkslayers.com/orbs/
+++
Note that the VM/CMS server which hosts the list I own is '142.104.5.230'.

Evidently, 'DorkSlayers' tests for "open" SMTP-servers,
such as are found in the current TCP/IP software for VM/CMS,
and publishes that information is some sort of "black-list",
and then refuses to accept all E-mail originating from such a host.

It makes sense, if you're an ISP trying to stop spam, and that's more important
than your customer's desire to access a mailing-list served by that host.

It doesn't bother me to be "blocked" by one ISP; however, if some person tries
to subscribe to a LISTSERV-controlled mailing-list which you own, you may get
a similar "bounce" message.  Such a person will have to switch ISPs,
to find one which does not use the 'DorkSlayers' system.

P.S.  DorkSlayers seem to be geographically "near" to me,
      but their telephone-numbers are totally bogus ...

  Dorkslayers International (DORKSLAYERS-DOM)
     1430 - 405 Granville St.
     Vancouver, BC V6C 1T2
     CA

     Domain Name: DORKSLAYERS.COM

     Administrative, Billing, Technical, Zone Contact:
        Sword, Dorkslayers  (DS6585)  [log in to unmask]
        +1 (604) 555-5555 (FAX) +1 (604) 555-5555

     Record last updated on 02-Oct-98.
     Record created on 06-Mar-97.

Vacuum 6 Closets, 1 Terrace Too.