DNS reverse lookup problem - NSlookup

[william-swc]

Hi,

 

We are having issues with reverse lookup on DNS. The scenario is this:

 

When I run nslookup command in the format "nslookup computername" eg nslookup ot11-wks01, it will contact the primary DNS server and return the correct IP address for that computer, in this example I will use 10.50.23.20 as the returned ip address.

 

If I then run nslookup on the IP address eg nslookup 10.50.23.20 it will return the FQDN of a completely different computer.

 

I believe this to be a reverse lookup problem. It may not seem important but we use 8e6 iR3000 as our web filter and review the websites students are viewing regularly. the r3000 returns IP addresses used to access websites and we need to be able to resolve the ip address to a computer name in order to locate the offending user in the college. We had an occasion recently where a student was falsely accused of accessing a computer in a staff area because nslookup returned the wrong computer name

 

My DNS settings on reverse lookup zones are:

Scavenging time 7 Days (actually another technician has just changed this to 1 hour for testing)

refresh interval 15 mins

expires after 1 day

Minimum Time to Live 1 hour

 

Under DHCP settings the DNS tab is

Enable DNS Dynamic updates (tick)

Always Dynamically update DNS A and PTR records (tick)

Discard A and PTR records when lease is deleted (tick)

Everything else unticked

 

There's alot of information there so thanks for anyone who took the time to read it and I hope someone can help.

[ReverseInternet]

We’ve recently launched new competitive research tool that allows you to do reverse IP lookups on websites just like myipneighbours.com and similar tools. But it also does much – more you can look up related websites based on Google Analytics and Adsense IDs and nameservers. The tool is FREE to use.

[_Adam_]

It is your DNS server, I had the exact same problem. Your settings look correct and I matched them to my server, unfortunately it was over 7 months ago I fixed it and cannot remember exactly what I did. I do remember I deleted all leases after hours just to clear them as scavanging was not grabbing all the old ones. If it comes back to me I will be sure to post but if you have any event viewer errors/warnings for DNS post them, it may jig my memory.