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Windows 2003 DNS scavenging records

Last Modified: 2008-04-24
I am running Windows 2003 SP1 with integrated DNS zones.
I have an issue where Host Records and ptr records are not being scavenged.  I am aware of how to fix, using the gui and dnscmd.  I need to use the /ageallrecords switch.  My question is this, ageallrecords will set todays date/time stamp so that when the next scavenging cycle happens they will be removed (if dns client doesnt update them)  This is fine for dynamic addresses such as clients but how will this setting effect servers with static address?  If I run this command am I going to find all my static addresses removed and in deep water?  Thanks in advance!  
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PberSolutions Architect

You're assumptions are correct

Be careful using /ageallrecords switch.  It does exactly what is says.  It ages all records including static ip addresses.  

Do you have aging and scavenging enabled on your DNS server?  
PberSolutions Architect

You should set your aging to match your DHCP intervals.  

A good guideline is: The no-refresh interval should match or be slightly lower than 50% of your DHCP lease.  The refresh should be the remainer of the lease.

i.e. DHCP lease 4 days
No refresh - 2 days
Refresh - 2 days.

Once aging is set on your zone, enable scavenging on only 1 DNS server (since AD replication will take care of the other DNS server since you mentioned your AD integrated).


I thought so.... I am currently using:
No-refresh 3 days
Refresh 1 days
Our DHCP servers are set to release after 3 days but also to release on computer shutdown (set at the DHCP server (option with windows 2000+))

So will static entries use dns client to refresh the lease?  Ie: I have servera with a static host and ptr record to, will servera use dnsclient to renew this static record and stop it getting scavenged?
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PberSolutions Architect

You are not alone with this problem.  Many companies see this same issue with DHCP and Dynamic DNS.  Usually they are laptop machines moving around or VPNing into the network.  Properly configured Aging and Scavenging helps most of the issues, but not all.  

Having DHCP update DNS instead of the client via the "Register this connection's addresses in DNS" setting also helps.  When the DHCP lease expires, the DHCP can be configured to remove the DNS entries.  We set this option on the scopes for conference rooms and the VPN subnets.

One word for the wise, don't set aging less than 24 hours.  This will cause scavenging of the domain SRV records which are updated every 24 hours or so.  And as you are probably aware, losing the SRV records is bad.

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