When you specify name servers in DNS they are defined by name. These first few names are typically names for name servers, so I believe these records are the names listed in the NS
records for the domain. I am concerned with the number of name servers, as normally there are 2 to 8 name servers for a domain. It appears the presented list of names also includes the names returned by looking up the addresses of the NS
servers.
The IP addresses listed should be the IP addresses obtained from the A
record for the names servers.
It is common for an IP address to have multiple associated names. PTR records are usually configured with only one name. Many ISPs by default configure their PTR records to indicate the service type, and some additional information. The names beginning adsl
appear to be of this form. With the exception of servers sending email to the Internet, there is no requirement to have names on PTR
records to match an A
record which points to them.
Try doing the lookups for yourself. You can use host
or nslookup
to find the IP address and corresponding PTR
names.
bill@localhost:~$ host ns1.maroc-telecom.com
ns1.maroc-telecom.com is an alias for dns.menara.ma.
dns.menara.ma has address 81.192.108.227
bill@localhost:~$ host 81.192.108.227
227.108.192.81.in-addr.arpa domain name pointer dns.menara.ma.
227.108.192.81.in-addr.arpa domain name pointer adsl-227-108-192-81.adsl.iam.net.ma.
You can use these commands to look up the name servers for the domain.
bill@localhost:~$ host -t NS example.com
example.com name server a.iana-servers.net.
example.com name server b.iana-servers.net.