Noel Erskine, Technology Coordinator Norris Schools

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Network Tech article - DNS and scavenging

Thursday, September 20, 2012

If you run your own DNS servers, which most Microsoft network admins do, you will want to have a good understanding of setting up scavenging of stale records. After a short time, especially with DHCP and computer imaging/cloning, you will notice a lot of duplicate DNS entries and stale records showing on your windows DNS servers.

The following are the articles / examples that will help your learn more about how scavenging can be set:
1. Understanding aging and scavenging:

A few handy DNS tests:

You can do an nslookup of your local domain, and only your DNS servers should be listed. for example, if your local windows domain is mynetwork.local  then you would do a nslookup mynetwork.local and should receive back the ip addresses of only your domain controllers.  (If you get more, then you have some issues!) 

Verify that that this destination domain controller is using a valid DNS server for DNS services, by running the DNS Enhanced version of DCDIAG.EXE command on the console of the destination domain controller, as follows: 

dcdiag /test:dns 

Remember, to flush dns on the local machine, the comand is: ipconfig /flushdns
Good steps to do this include these commands:
net stop dns
net stop logon
ipconfig /flushdns
net start dns
net start logon

To Sync your Domain controllers: Repadmin /syncall  More info on this Technet article

That's it for now. :)


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