Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '109.172.16.0'
+1.304
ERRNo PTR record availible DNS server 'ns1.ptn.ru' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.16.172.109.in-addr.arpa'.