According to what Eric has explained, Listserv doesn't send Ack-mailings
to domain addresses. But there seems to be a nice loophole between
1.5i and 1.5j. Since a few days (just since 1.5j was installed here)
I see occasionally rejected ack-mailings for the TCPIP-L list.
Unfortunately not all of these mailings were rejected and some people
were annoyed (you know, Arpa is such a perfect network so that nobody
see any reason for any kind of acknowledgement :-)
 
Apparently 1.5i doesn't send ack-mailings to domain addresses. But if
there is no ack= keyword in the list header (it was unfortunately
omitted on this list, which didn't any harm until now), the mail
forwarded to the next peer contains ACK in one of LSV... headers.
And this seems to overwrite the 'no-ack-to-domain-addresses' strategy
in 1.5j.
 
If you have peered lists which are gatewayed from Arpa-lists, ensure that
there is a Ack= No in the header. Optionally you may waste some time
answering complains by annoyed contributors from Arpa-land and catching
those ack-mailings before Mailer blows them onto the net. And don't
believe that it will be sufficient to inform the other list owners when
Ack= NO is missing, at least one of them will forget to fix his list.
And of course when you try to fix it yourself (a) some important link
will be down, or (b) the pw's don't match, or (c) you are not an owner
for that particular peer list (and of course arbitrary combinations
of (a), (b), and (c)).
 
  Thomas
 
P.S.: This letter is intended as an information to list owners, NOT as
base for discussions about inter-version compatibility, who is the
guilty, and how hard it is to maintain peered lists. But when I ever
meet that guy who invented computer networks in a dark alley ...