NSLOOKUP fails - reverse DNS issue?

[Koldov]

Not quite sure what I've done wrong here....

 

Doing an NSLOOKUP for an IP within the Domain results in this:

 

 

Checking the reverse DNS section on the DC, I can see that it is populated with a few entries (ones that have been configured with a static IP) and these do return a correct result obviously.

 

But none of the other machines on the network appear here (even some of those with static IPs)...

[localzuk]

What do you have set up as your reverse lookup zone(s)?

[Koldov]

What do you have set up as your reverse lookup zone(s)?

 

Not quite sure I follow...

 

Hopefully a picture is worth a thousand words!

 

[localzuk]

So, in the 2.10.in-arpa one, is the address you are trying to reverse DNS listed?

 

If I go into one of my reverse lookup zones, there are IP addresses listed, with the data showing the hostname. These get populated by the DHCP server IIRC, as the 2 are integrated.

[Koldov]

Some are listed there and these are the ones that return the correct result in NSLOOKUP (is that the way it should work?).

 

However, for example - NSLOOKUP 10.2.153.32 - returns Non-existent domain (maybe because this entry doesn't appear in the 'Reverse Lookup Zone').

 

But I can do - NSLOOKUP ICT-01 - and this will return the IP 10.2.153.32 (as it is in the 'Forward Lookup Zone').

 

Is this the expected behaviour?

 

But if what you are saying is correct then that may be my problem, as DHCP is run by our managed switches and not by the server...

 

It might be, as it seems that the only entries that appear in the 'Reverse Lookup Zone' are ones that I have entered manually into the machines for a 'Static' I.P.

 

Although there seems to be 2 random entries for computers I don't remember setting an I.P. for (can't check at the moment as the room is in use)!

[localzuk]

Yeah, if there's no PTR in the reverse lookup zone, you won't get a valid response doing a reverse lookup.

 

Yeah, that seems like your issue - if you're not using the MS DHCP server, then no dynamically assigned machines will get reverse zone records added.

 

So, you're seeing what you should then.

[CCCSecMan]

Your reverse lookup zone ought to be a /24 not a /16. This will not be helping and might even be causing the problem.

 

i.e if your network is 10.2.0.0/23 then you should have two reverse lookup zones:

 

0.2.10.in-addr.arpa

1.2.10.in-addr.arpa

 

Also ensure the DHCP server is setting the DNS suffix value correctly as otherwise it will not work correctly. You could also try experimenting with "Computer Configuration\Administrative Template\Network\DNS Client\Register PTR Records" GPO settings and similiar.