A seldom used DNS Blacklist is causing email delivery problems for some of our customers.  Apparently this list has been abandoned by the operator.  It had been returning a Not listed result for all IP addresses checked.  As of a few days ago, the domain registration lapsed and Network Solutions pointed the DNS servers to:

  NS1.PENDINGRENEWALDELETION.COM 205.178.190.51
  NS2.PENDINGRENEWALDELETION.COM 205.178.189.51

This is causing ALL IP ADDRESSES to be listed.  Our systems sent email alerts to all of our free monitoring service customers today, and anyone using our free lookup tool will find their server listed now.  This listing is bogus and we will remove the list from our lookup tools by the end of the day.

However, some email server administrators have their servers set to BLOCK email from servers listed on this blacklist.  This is causing them to reject ALL incoming emails.  Presumably, they got away with using this list without false positives, because nothing was listed before.  This problem is not wide spread, but significant enough that we are getting calls on it.

If you receive bounce messages from a recipient based on this blacklist, you should contact the administrator of that system and inform him or her of the problem.