DNS issues with old time stamps

crp0499
crp0499 used Ask the Experts™
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So I inherited a domain that's 15 years old.  It's DNS has NEVER been scavenged or cleaned up to speak of and it's showing.  I have records with time stamps of tens years ago, five years ago, etc.  I also have multiple A records for DNS names associated with the same IP.  It's generally messy.

In my start to cleaning it up, my first issue is that apparently my PCs and servers are not refreshing properly.  Here's why I say that.

I have a server that is in production and it answers pings.  It of course has a statically assigned IP address.  In DNS, it has a time stamp, which I understand, but the time stamp is seven years old.  I expected that when the server refreshed, the time stamp would update, BUT, have no scavenging settings set, so maybe that's why no refresh.  If I turn on scavenging, I'll lose servers with old time stamps when in reality, they are active.

So, can anyone tell me why I have servers with five year old time stamps that are not refreshed?  I mean I expect the servers to refresh their live status and DNS to change the time stamp.

Thanks!
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Will SzymkowskiSenior Solution Architect
Most Valuable Expert 2015
Top Expert 2015
Commented:
Static "Timestamp" addresses are automatically filtered out of the Scavenging and Aging process. All other records that are Dynamic "should" automatically update their timestamp (static or dynamic) use the DNS Client Service to update their DNS timestampe.

What you can do is try ipconfig /registerdns command and see if the timestamp changes.

Will.
crp0499CEO

Author

Commented:
Will, are you telling me those servers with those old time stamps will not be removed based on the time stamp?
Will SzymkowskiSenior Solution Architect
Most Valuable Expert 2015
Top Expert 2015
Commented:
If you enable Scavenging those servers will get removed if the timestamp is outside of what you have set  for the scavenging parameters.

I am saying go to those servers that have "out of date" timestamps and run ipconfig /registerdns to see if it updates the DNS recrods on the server.

I would do that before considering enabling this feature.

Will.
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crp0499CEO

Author

Commented:
It DID update it's time stamp.
Will SzymkowskiSenior Solution Architect
Most Valuable Expert 2015
Top Expert 2015
Commented:
As long as the timestamp is outside of the scavanging and aging it will not remove these entries.

Will.
Top Expert 2014
Commented:
I almost always provide this link to someone with questions about scavenging.  It is very comprehensive.
http://blogs.technet.com/b/networking/archive/2008/03/19/don-t-be-afraid-of-dns-scavenging-just-be-patient.aspx

If you don't have aging settings configured on a zone, timestamps won't replicate, so your view could be different on different DCs.

For more info about how dynamic DNS, DHCP, and scavenging all relate, I also recommend:
http://blogs.technet.com/b/askpfe/archive/2011/06/03/how-dns-scavenging-and-the-dhcp-lease-duration-relate.aspx
http://blogs.msmvps.com/acefekay/2009/08/20/dhcp-dynamic-dns-updates-scavenging-static-entries-amp-timestamps-and-the-dnsproxyupdate-group/
crp0499CEO

Author

Commented:
I'm thinking as a fix, running a powershell to force every PC/Server on the domain to re register in DNS and then turn on scavenging.  

Thoughts Will and footech?
Top Expert 2014
Commented:
That's fine.  But as mentioned in the first link I gave, don't be in a rush.  You can run the command to force a machine to register, but what you really want to do is monitor the situation and verify that machines are automatically updating their records going forward.  Otherwise sometime in the future records will be scavenged that you don't want (though often the situation will clear up when the client registers again).  It's also good to note that when you have clients that hop around and change IPs, you will have periods where the record isn't up-to-date, but with scavengening these will cleared up so they don't hang around too long.
crp0499CEO

Author

Commented:
Foo, what i don't understand is that live, active machines are not refreshing their time stamps at reboot, etc.  I have machines with seven year old time stamps.  THAT concerns me.
Top Expert 2014
Commented:
Ownership of an existing record could be blocking some clients from updating a record.

And we haven't gone through what your aging settings are for zones, what your dynamic update settings are, etc.  That's the why for the recommended reading, so you can better understand all these interactions.  Group Policy and NIC settings are also available that can change update behavior.
crp0499CEO

Author

Commented:
ok, I'll run with what I have then.  Thanks buddy!

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