Dhcp updating dns records
Hello, I have just a general question, and havent had any luck searching for the answer, any information or direction would be greatly appreciated, here are the details: Right now DHCP on our network is handled by a Catalyst switch 4506, but the problem is it is not updating our DNS, like as in a windows Active Directory Integration Zone. Is there a way/commands to have the Cisco switch update our Windows DNS server when a DHCP clients lease is up, or is released? If the clients happen to pick up their IP from the server then all is fine but if they get it from the router's DHCP then the DNS record on the server does not get updated even though dynamic updates is set to 'nonsecure and secure'.If they're being assigned ISP DNS servers from the router when they get their ip addresses from the router then they're going to try to register/update their A records with those ISP DNS servers.A network capture of traffic exiting your network will probably confirm that.Ace Fekay, MCT, MVP, MCITP EA, Exchange 2010 Enterprise Administrator, MCTS Windows 2008, Exchange 2010 & Exchange 2007, MCSE 2003/2000, MCSA Messaging 2003 Microsoft Certified Trainer Microsoft MVP: Directory Services Active Directory, Exchange and Windows Infrastructure Engineer Compiled 4/2006, recompiled 7/2009, & 1/4/201011/30/2011 – added DHCP credentials and DHCP/DNS tab properties screenshots.3/10/2012 – Added enabling DNS scavenging screenshots.8/22/2012 – Verified with a Microsoft enginner, we need to use the Dns Update Proxy group and configure credentials to work, not one or the other. Also fixed missing screenshots8/3/2012 – Additional info about DHCP Name Protection and that it requires Credentials, Dns Update Proxy, but more so to secure the Dns Update Proxy group .
What DNS server are the clients configured with when the router gives them a DHCP lease?If you're having a problem with your internal DNS server that's then making you use the router for DHCP and DNS then the fix is to resolve the problem with the DNS server.When you say "DNS on the server doesn't seem to get updated with the latest IP number" can you explain what you mean and what the symptomes of the problem are?Maybe have the router's DHCP point to the server as primary DNS, and the other DNS servers as secondary?As Shane stated in his comment, in order for the DHCP clients to update their A records in your internal DNS server they need to be configured to use that DNS server.
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You can use the following registry subkey to modify the TTL value: HKEY_LOCAL_MACHINE\SYSTEM\Current Control Set\Services\Tcpip\Parameters\Default Registration TTL . Scavenging Refresh and No Refresh settings must be equal to or less than the lease period.