Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '210.233.173.0'
+1.580
ERRNo PTR record availible DNS server 'dns.knet.ad.jp' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.173.233.210.in-addr.arpa'.