Another random blacklisting of my mail server IP:

    553 5.3.0 alph732 DNSBL:RBL 521< x.x.x.x >_is_blocked. \
    For assistance forward this error to abuse_rbl@abuse-att.net

This time from AT&T. Sigh. At least they were responsive to my email
and removed the block within a week. Still, there is zero reason to
block my little mail server and this just exposes the problems with
email blacklists. They can't possibly get all of the spammers, and
are frequently prone to false-positives. My prior commentary:

[0]: gopher://gopher.unixlore.net/0/glog/private-email-servers-dying.md
[1]: gopher://gopher.unixlore.net/0/glog/mail-server-blacklist-woes.md
[2]: gopher://gopher.unixlore.net/0/glog/email-posting-styles-and-blacklist-update.md