Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '157.248.21.0'
+138
ERRNo PTR record availible DNS server 'a7-67.akam.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.21.248.157.in-addr.arpa'.