AT&T customers have contacted us saying they can't reach any of our DNSBLs, seems AT&T have defined a fake sbl.spamhaus.org zone in their DNS servers so when AT&T customers ask AT&T's NS 12.149.189.2 for sbl.spamhaus.org they get:
;; ANSWERS:
sbl.spamhaus.org 86400 IN SOA loopback root.loopback (
1 ; serial
3600 ; refresh
600 ; retry
3600000 ; expire
86400) ; minimum
;; AUTHORITY RECORDS:
sbl.spamhaus.org 86400 IN NS loopback
;; ADDITIONAL RECORDS:
loopback 61703 IN A 127.0.0.1
And it's not just affecting our users...
blackholes.mail-abuse.org 86400 IN SOA loopback root.loopback
blackholes.mail-abuse.org 86400 IN NS loopback
loopback 61520 IN A 127.0.0.1
cbl.abuseat.org 86400 IN SOA loopback root.loopback
cbl.abuseat.org 86400 IN NS loopback
loopback 61480 IN A 127.0.0.1
list.dsbl.org 86400 IN SOA loopback root.loopback
list.dsbl.org 86400 IN NS loopback
loopback 60855 IN A 127.0.0.1