Round Waffle wrote: But when you actually ftp to ftp.eff.org, the hostname reported is kragar.eff.org, and a traceroute there shows the endpoint's IP address as 192.88.144.4. Creative DNS administration... The dig output explains what's going on. $ dig ftp.eff.org ; <<>> DiG 2.0 <<>> ftp.eff.org ;; ->>HEADER<<- opcode: QUERY , status: NOERROR, id: 6 ;; flags: qr aa rd ra ; Ques: 1, Ans: 2, Auth: 0, Addit: 0 ;; QUESTIONS: ;; ftp.eff.org, type = A, class = IN ;; ANSWERS: ftp.eff.org. 86400 CNAME kragar.eff.org. kragar.eff.org. 86400 A 192.88.144.4 ;; Sent 1 pkts, answer found in time: 158 msec ;; FROM: inet to SERVER: default -- 0.0.0.0 ;; WHEN: Wed Aug 11 11:44:15 1993 ;; MSG SIZE sent: 29 rcvd: 73 In other words, ftp.eff.org is an alias for the official name of the host. Quite properly, the inverse map lists the official name for the host: $ dig -x 192.88.144.4 ; <<>> DiG 2.0 <<>> -x ;; ->>HEADER<<- opcode: QUERY , status: NOERROR, id: 6 ;; flags: qr aa rd ra ; Ques: 1, Ans: 1, Auth: 0, Addit: 0 ;; QUESTIONS: ;; 4.144.88.192.in-addr.arpa, type = ANY, class = IN ;; ANSWERS: 4.144.88.192.in-addr.arpa. 86400 PTR kragar.eff.org. ;; Sent 1 pkts, answer found in time: 329 msec ;; FROM: inet to SERVER: default -- 0.0.0.0 ;; WHEN: Wed Aug 11 12:45:52 1993 ;; MSG SIZE sent: 43 rcvd: 71 But by advertising the name ``ftp.eff.org'', instead of ``kragar.eff.org'', the administrator gains the flexibility to move the archive to some other machine if necessary/desirable. That's exactly the right way to run such a service.