Judging by recent spamassassin-users mailing list messages, Verizon is
hijacking DNS responses that seem to be invalid and replacing them
with their own responses (in oder to drive traffic to their search
sites). Naturally this breaks SURBL lookups. If you are using
Verizon's nameservers and are getting false positives, you may want to
check into this.
Here's one reference:
http://www.freedom-to-tinker.com/?p=1227
Jeff C.
