|If you're running a LISTSERV list, one way to pretty much seal out spammers
|is to use the SUBSCRIPTION=By Owner option along with SEND=Private. You'll
|need to approve every person who joins the list, but that barrier should be
|effective against virtually all mailspammers.
We started to switch our majordomo list to this config.
It already requires subscription approval, but tying
senders to users wouldn't work, because many of the members
post from multiple accounts, or at least multiple systems
within domains that don't hide system names. This requires
maintaining a separate list of posters from members, and
in a couple of cases, would require many, many entries for
one person (some ISPs give dialup SLIP/PPP customers a
system name based on the line they dial in on, as in