From (Solaris 11.1 with current patches, m4000 128GB) syslog:Jun 17 10:06:14 sun-m4k-03 sendmail[4993]: [ID 702911 mail.warning] gethostbyaddr(10.128.4.50) failed: 1The ip is valid from the commandline:ping 10.128.4.5010.128.4.50 is alivenslookup appears to reverse the octets when doing a lookup: nslookup 10.128.4.50Server:         10.128.8.18Address:        10.128.8.18#53** server can't find 50.4.128.10.in-addr.arpa.: NXDOMAINTried a search on the internet - no luck
Solaris 11 nslookup reverses ip
dns
This is correct.  Reverse DNS lookups are performed by querying the PTR record for the IP address in the .in-addr.arpa domain.  DNS names have the least significant/least broad component first, so octets of the IP address, which are written with the most significant/most broad component first, are put in the reverse order so that each class of network can have a DNS zones.If you want to support reverse DNS lookups on private IP addresses, you will have to configure a zone for 10.in-addr.arpa. to hold the PTR record for 50.4.128.10.in-addr.arpa..