2008 DNS and DHCP question

We’re AD 2008 R2 (2 sites, 2 DCs each site) and if I look in DNS under the forward lookup zone for ourcompany.com, for some I can see the same IP assigned for up  to 3 hosts.
If I ping-A the 3 host it comes back with same IP for all 3 hosts.  If I ping-a the IP address it comes back with the hostname for the host with the latest s timestamp on the record. I guess it’s something to do with DHCP?

We don’t  seem to be having any problems but I don’t imagine it’s good!

2 questions please:

How do I fix with no disruption to PCs?
How is it I ping 3 hostnames and they return the same IP, I guess they have other IPs but I can’t see these in DNS.

Cheers
kswan_expertAsked:
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moorenetworkCommented:
To answer your questions:
1. You can delete the DNS entries for the incorrect hosts, this should not disturb current traffic, legitimate traffic that is meant for one of those hosts may currently be getting interrupted because of this problem.  The fact that you have several with the same name is a little suspicious, make sure if any of them has a static (manually typed in IP) that you add them to your DHCP server with the correct reservations so that other hosts don't get the same IP
After adding the proper reservation do an ipconfig /release and ipconfig /renew on any client that needs to change IPs (assuming they are pulling from DHCP)

2. when you first resolve a hostname your computer caches the result for a set period of time (the time changes based on your version of Windows).  if you did a ping from 5 different PCs the chances are you would see all 3 IPs at least once
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JaihuntCommented:
DNS scavenging enabled in your environment.? What is the lease period set for the scopes.?

Check enable Allways dynamically update DNS A and PTR Records in DHCP

Enable the scavenging in your DNS. Please check below links,

http://blogs.technet.com/b/networking/archive/2008/03/19/don-t-be-afraid-of-dns-scavenging-just-be-patient.aspx

http://msmvps.com/blogs/acefekay/archive/2009/08/20/dhcp-dynamic-dns-updates-scavenging-static-entries-amp-timestamps-and-the-dnsproxyupdate-group.aspx
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Windows Server 2008

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