The reverse lookups for the RFC-1918 address space are broken again, or still. $ dig -x 172.16 any @blackhole.isi.edu ; <<>> DiG 8.1 <<>> -x any @blackhole.isi.edu ; (1 server found) ;; res options: init recurs defnam dnsrch ;; res_send to server blackhole.isi.edu 128.9.64.26: Connection timed out blackhole.isi.edu and rs0.internic.net are timing out, while ns2.internic.net is giving wrong answers: $ dig -x 192.168.1.1 @ns2.internic.net ; <<>> DiG 2.2 <<>> -x @ns2.internic.net ; (1 server found) ;; res options: init recurs defnam dnsrch ;; got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 10 ;; flags: qr rd; Ques: 1, Ans: 0, Auth: 0, Addit: 0 ;; QUESTIONS: ;; 1.1.168.192.in-addr.arpa, type = ANY, class = IN ;; Total query time: 145 msec ;; FROM: valis.worldgate.com to SERVER: ns2.internic.net 198.41.0.11 ;; WHEN: Fri May 29 01:33:24 1998 ;; MSG SIZE sent: 42 rcvd: 42 $ dig -x 192.168.1.1 @blackhole.isi.edu ; <<>> DiG 2.2 <<>> -x @blackhole.isi.edu ; (1 server found) ;; res options: init recurs defnam dnsrch ;; res_send to server blackhole.isi.edu 128.9.64.26: Operation timed out Heck, not having any servers for the space is a lot better than the current situation. It makes traceroutes over links using private address space (it happens and some people recommend it, even though I'm not fond of the idea...) annoying.