Isn't there also a setting in the DHCP scope that let's it update the DNS ?
This article may help... http://support.microsoft.com/kb/816592 ________________________________ From: tony patton <tony.pat...@quinn-insurance.com> To: NT System Admin Issues <ntsysadmin@lyris.sunbelt-software.com> Sent: Wed, August 25, 2010 8:50:03 AM Subject: Re: DHCP and DNS Anomoly Yep, thats a common problem we have, it's due to DNS scavenging not being configured, can't get them to change it either. 2 1/2 weeks and it ain't my problem anymore :) Regards Tony Patton Desktop Support Analyst - Cavan Ext 8078 Direct Dial 049 435 2878 email: tony.pat...@quinn-insurance.com From: "Bob Hartung" <bhart...@wiscoind.com> To: "NT System Admin Issues" <ntsysadmin@lyris.sunbelt-software.com> Date: 25/08/2010 14:37 Subject: DHCP and DNS Anomoly ________________________________ I've got an odd situation with DHCP and DNS creating a confusing situation. I use SmartCode VNC Manager for remote support. Every hour it queries all our network PCs to see if they are active or not. It uses the PC's name to resolve the IP address. I happened to notice that a very low use PC showed active when I was pretty confident it wasn't turned on. When I remoted into it, it turned out to be a different PC. Hmmm... I went to the command prompt and tried pinging both the low use PC as well as the PC I wound up connecting to and they both resolved to the same IP address. I tried "ipconfig /flushdns" to see if I had an error in the DNS cache but that made no difference. Next stop was the DHCP server. We have a MS Window 2003 SP2 PDC that hosts both DNS and DHCP. The low use PC had been off long enough that there wasn't even an entry for it in the IP address leases. There was an entry for the PC I wound up connecting to. I tried the same ping testing on the PDC as I had on my PC and got the same results. Next stop was the DNS server. Ah ha! There were 2 entries in the Forward Lookup Zones for that IP address for each of the PCs I was pinging. Oddly, in the Reverse Lookup Zones, there was only one entry and it was for the low use PC. It's strikes me odd that DNS would allow multiple entries for the same IP address. Is that normal behavior? Since these pointer records are automatically created by an interaction between the DHCP and DNS servers, shouldn't there also be a process that would delete DNS pointers based on expired DHCP leases, particularly since the IP address had been handed out to a different PC? I know I could resolve this issue by either turning on the low use PC and getting a new IP address lease or by simply deleting the expired DNS pointer but I'd like to understand why this can happen and if there's a way to configure things so it doesn't continue to happen. Thanks. ---------------------- Bob Hartung Wisco Industries, Inc. 736 Janesville St. Oregon, WI 53575 Tel: (608) 835-3106 x215 Fax: (608) 835-7399 e-mail: bhartung(at)wiscoind.com This e-mail is intended only for the addressee named above. The contents should not be copied nor disclosed to any other person. Any views or opinions expressed are solely those of the sender and do not necessarily represent those of QUINN-Insurance Limited (Under Administration), unless otherwise specifically stated . As internet communications are not secure, QUINN-Insurance Limited (Under Administration) is not responsible for the contents of this message nor responsible for any change made to this message after it was sent by the original sender. Although virus scanning is used on all inbound and outbound e-mail, we advise you to carry out your own virus check before opening any attachment. We cannot accept liability for any damage sustained as a result of any software viruses. ==================================================================== QUINN-Insurance Limited (Under Administration) is regulated by the Financial Regulator and regulated by the Financial Services Authority for the conduct of UK business. ==================================================================== QUINN-Insurance Limited (Under Administration) is registered in Ireland, registration number 240768 and is a private company limited by shares. Its head office is at Dublin Road, Cavan, Co. Cavan. This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
