I noticed this in the logs as well. Oct 17 08:20:55 fileserver sshd[3857]: reverse mapping checking getaddrinfo for ar-sd.net.155.77.82.in-addr.arpa failed - POSSIBLE BREAKIN ATTEMPT! This is one of the locations from where I connect remotely. Tried to fix this... but still got the error.
All this means is that there is no PTR record for that IP address. In order to get these out of your logs just ask your provider to set the PTR's up correctly. [root@mail ~]# dig -x 82.77.155.72 ; <<>> DiG 9.3.1 <<>> -x 82.77.155.72 ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50823 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1 ;; QUESTION SECTION: ;72.155.77.82.in-addr.arpa. IN PTR ;; ANSWER SECTION: 72.155.77.82.in-addr.arpa. 86400 IN PTR ar-sd.net.155.77.82.in-addr.arpa . ;; AUTHORITY SECTION: 155.77.82.in-addr.arpa. 86400 IN NS ns3.rdstm.ro. 155.77.82.in-addr.arpa. 86400 IN NS ns.rdstm.ro. ;; ADDITIONAL SECTION: ns.rdstm.ro. 86358 IN A 193.231.233.1 ;; Query time: 219 msec ;; SERVER: 209.212.96.1#53(209.212.96.1) ;; WHEN: Tue Oct 18 06:54:38 2005 ;; MSG SIZE rcvd: 126 *** BUT ar-sd.net.155.77.82.in-addr.arpa does not resolve... [root@mail ~]# dig ar-sd.net.155.77.82.in-addr.arpa ; <<>> DiG 9.3.1 <<>> ar-sd.net.155.77.82.in-addr.arpa ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 3472 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;ar-sd.net.155.77.82.in-addr.arpa. IN A ;; AUTHORITY SECTION: 155.77.82.in-addr.arpa. 10645 IN SOA ns.rdstm.ro. tech.rdstm.ro. 2005062903 10800 3600 345600 86400 ;; Query time: 2 msec ;; SERVER: 209.212.96.1#53(209.212.96.1) ;; WHEN: Tue Oct 18 06:56:32 2005 ;; MSG SIZE rcvd: 102