Delete old / inactive DHCP reservations

Question

_{Monday, August 15, 2011 8:23 AM}

Hi,

we use the 2008R2 DHCP Server. In the past massive dhcp entries were made not only for accesspoints and printers but for all PCs. So there are a
lot of reservations that aren't active any more. A lot of those PCs don't exist anymore and I was hoping there's a way to clean those inactive reservations.

Maybe I can do this with the help of some Logs like the audit log?!

If someone knows a tool that's able to do this job it would be great.

Thanks a lot!

All replies (6)

_{Tuesday, August 16, 2011 3:13 AM ✅Answered}

Hi Tomas,

Thanks for posting here.

Based on my knowledge there is no such tool can help to detect these inactive DHCP reservation entries so far . However you may consider to customize a program or script to monitor or verify DHCP lease logging in order to count and find out the most active entries .

Audit logging

http://technet.microsoft.com/en-us/library/cc758251(WS.10).aspx

Analyzing server log files

http://technet.microsoft.com/en-us/library/cc776384(WS.10).aspx

Posting to scripting guys forum may help you acquire such script:

http://social.technet.microsoft.com/Forums/en/ITCG/threads

Meanwhile, the utility below should also helpful for you to manage your DHCP reservations:

Reservation Manager - A tool to manage reservations

http://blogs.technet.com/b/teamdhcp/archive/2006/09/19/dhcp-reservation-tool.aspx

Regards,

Tiger Li

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact  [email protected].

Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

_{Tuesday, August 16, 2011 9:17 PM ✅Answered}

Port scan each subnet to see what is there, do the same thing a week later and compare results. If you have "ghost" reservations record their mac and IP and remove them a handful at a time being sure to keep their records in an excel sheet in case you need to put them back.

This will be a manual process, there isn't a way to cleanly script it without risk of impacting your production.

_{Friday, August 19, 2011 9:01 AM ✅Answered}

Here is my update,

I printed out a list of all ips my inventory software has scanned and now lucky one will get this list and can delete those entries that didn't get scanned in the past 90 days.

Thanks!

_{Monday, August 15, 2011 10:20 AM}

Hallo Thomas,

dieses Forum ist in englischer Sprache, somit übersetze bitte Deine Frage oder nutze die deutsche Version dieses Forums.

Hier ist eine Übersicht der deutschsprachigen: http://social.technet.microsoft.com/Forums/de-DE/categories

Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.

_{Monday, August 15, 2011 11:41 AM}

Hi Meinolf,

sorry ich hab Anfangs im Exchange (2010) Forum in engl. gepostet weil es vor der Anmeldung engl. Beiträge gezeigt hatte und nach der Anmeldung + post wurde mir nahegelegt in dt. zu posten. Hier isses andersrum - naja...

_{Wednesday, August 17, 2011 11:25 AM}

Hi Tomas,

If there is any update on this issue, please feel free to let us know.

Regards,

Tiger Li

TechNet Subscriber Support in forum
If you have any feedback on our support, please contact  [email protected].

Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.