DNS records are not 100% correct

Question

For a while now we've been noticing that some DNS records are not correct. The records are pointing to incorrect IP addresses. One by one I open the record, update the IP, then replicate across all domain controllers.
What would cause the hostname of one machine to point to another IP address?

Answer 1

I believe what you're seeing is from DHCP-DNS registration. You may have duplicates, or incorrect data for records that can't be updated by DHCP service or the DHCP client due to permissions on the record. You may also not have scavenging in place.
In summary:
Configure DHCP Credentials. The credentials only need to be a plain-Jane, non-administrator, user account. But give it a really strong password.
Set DHCP to update everything, whether the clients can or cannot.
Set the zone for Secure & Unsecure Updates. Do not leave it Unsecure Only.
Add the DHCP server(s) to the Active Directory, Built-In DnsUpdateProxy security group. Make sure ALL other non-DHCP servers are NOT in the DnsUpdateProxy group. For example, some believe that the DNS servers or other DCs not running DHCP should be in it.
They must be removed or it won't work. Make sure that NO user accounts are in that group, either. (I hope that's crystal clear - you would be surprised how many will respond asking if the DHCP credentials should be in this group.)
On Windows 2008 R2 or newer, DISABLE Name Protection.
If DHCP is co-located on a Windows 2008 R2 or Windows 2012 DC, you can and must secure the DnsUpdateProxy group by running the following:
dnscmd /config /OpenAclOnProxyUpdates 0
Configure Scavenging on ONLY one DNS server. What it scavenges will replicate to others anyway. Set the scavenging NOREFRESH and REFRESH values combined to be equal or greater than the DHCP Lease length.
For specifics and step by steps, and good discussions on what's going on in the background and what to expect:
DHCP Service Configuration, Dynamic DNS Updates, Scavenging, Static Entries, Timestamps, DnsUpdateProxy Group, DHCP Credentials, prevent duplicate DNS records, DHCP has a "pen" icon, and more...
http://msmvps.com/blogs/acefekay/archive/2009/08/20/dhcp-dynamic-dns-updates-scavenging-static-entries-amp-timestamps-and-the-dnsproxyupdate-group.aspx  
Good summary
How Dynamic DNS behaves with multiple DHCP servers on the same Domain?
http://social.technet.microsoft.com/Forums/en-US/winserverNIS/thread/e9d13327-ee75-4622-a3c7-459554319a27
Another good Summary:
Thread: "DNS problem" December 18, 2013
http://social.technet.microsoft.com/Forums/windowsserver/en-US/37b8b6b3-6cb1-496c-8492-09ded13bab18/dns-problem?forum=winserverNIS
Ace Fekay
MVP, MCT, MCITP/EA, MCTS Windows 2008/R2 & Exchange 2007, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
Technical Blogs & Videos: http://www.delawarecountycomputerconsulting.com/
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