Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '3.172.15.0'
+153
ERRNo PTR record availible DNS server 'pdns1.ultradns.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.15.172.3.in-addr.arpa'.