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Question
Thursday, February 11, 2010 10:30 AM
Hi.
I have changed some computers on my company's network, deleted certain reservations (Windows Server 2003), and now, when I want to add new reservation, I get the following message: "The specified IP address or hardware address is being used by another client".
- Yes, the new computer IS connected to the network.
- Yes, MAC address IS correct.
- No, the IP address IS NOT used by any other computer. No ping, no nslookup, no DNS record for the IP address.
- I am positive that the MAC address is not the issue here, but the IP address that was reserved for another, old computer that is not in use anymore.
Believe it or not, I had the same problem last year and I have resolved it, but I don't remember how :) It had something to do with some log file on the server (I don't know which). Now I am totally stuck and I hope someone here can help me.
Thank you in advance.
All replies (14)
Thursday, February 11, 2010 2:23 PM
Could you please check the IP address lease
Thursday, February 11, 2010 3:27 PM
Thanks for replying, Sameh.
The address is not leased at all, it is a free IP address, as stated before. The issue here is some old record related to the ip address reservation that exists somewhere and needs to be found. I tried netsh dump but there is no record on this IP adress. Basically, I need to discover which mac address was dedicated to the IP adress so I can netsh delete reservedip or something like that...
Sunday, February 28, 2010 8:19 AM | 1 vote
Hey you can ping these IP address from your computer then use ARP -a command to determine Mac address for each IP your machine talked with it
Wednesday, December 1, 2010 4:04 PM
Iam having the same problem. What could be the cause? In my case whenever I add a reservation it says "IP is not available"
Wednesday, December 1, 2010 5:15 PM | 2 votes
Iam having the same problem. What could be the cause? In my case whenever I add a reservation it says "IP is not available"
What operating system?
Do you see a "BAD ADDRESS" entry in the lease list?
Take a look at these articles:
The "Lease duration for DHCP clients" option is set to 0 and some DHCP scope options disappear on a Windows Server 2003-based DHCP server
http://support.microsoft.com/kb/936009
Reservations are deleted incorrectly from a DHCP server that is running Windows Server 2008 R2
http://support.microsoft.com/kb/981776
DHCP Reservations fail with "Specified address is not available" and more!
http://community.spiceworks.com/topic/105008
Ace
Ace Fekay
MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
This posting is provided AS-IS with no warranties or guarantees and confers no rights.
Thursday, December 2, 2010 5:21 AM
Thank you for your reply Ace, Iam using Server 2003. My reservations only reached half of the ip addressed on the scope but whenever I add additional reservation it says "IP is not available". The IP that Iam assigning is not yet added and same with the MAC. What could be the problem?
Thursday, December 2, 2010 3:24 PM | 1 vote
Not sure at this point. Did you check the links I posted? Check the first and third link.
Ace
Ace Fekay
MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
This posting is provided AS-IS with no warranties or guarantees and confers no rights.
Friday, December 3, 2010 4:03 AM
Thank you Ace for the links....You're a savior.
Friday, December 3, 2010 4:36 PM
You are welcome!
Curious, which link or suggestion I offered helped, and what was the resolution?
Ace
Ace Fekay
MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
This posting is provided AS-IS with no warranties or guarantees and confers no rights.
Thursday, December 15, 2011 4:59 PM
Does anyone know if there's a fix for Win2003 server R2 SP2?
There's just one for 2008 64bit :(
Thursday, December 15, 2011 5:25 PM
Didn't this one help?
The "Lease duration for DHCP clients" option is set to 0 and some DHCP scope options disappear on a Windows Server 2003-based DHCP server
http://support.microsoft.com/kb/936009
Ace Fekay
MVP, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007 & Exchange 2010, Exchange 2010 Enterprise Administrator, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php
This posting is provided AS-IS with no warranties or guarantees and confers no rights.
Wednesday, April 25, 2012 12:55 PM | 2 votes
1. Run: netsh dhcp server dump > c:\texfile.txt
2. Searched text file created for MAC causing the problem which showed MAC related to another reservation although correct MAC was showing in DHCP admin.
3. Deleted and re-created reservation with correct values
4. Was then able to use MAC address for the problem reservation
If the MAC does not show in the dump file created
1. Run netsh dhcp server scope SCOPENAME initiate reconcile, which showed one inconsistent IP address that does not show in DHCP Admin GUI
2. Assumed this to be the erroneous entry and run netsh dhcp server scope SCOPENAME delete reservedip RESERVEDIP erroneousMAC (erroneousMAC=MAC unable to add) which completed successfully freeing the MAC address for use
3. Added new reservation
By Ben2509
Friday, June 12, 2015 3:19 PM
I found it by trying to add the MAC address to the MAC Deny List, so that I could get a router to do the DHCP server job with the scope of IPs that I needed. It's not anything what Windows says is the problem. It's that Windows doesn't except the MAC address under Reservations using the normal syntax or notation using colons.
Just enter the MAC without ":"... Just the numbers and letters! No colons! You can use hyphens, "-"... But not colons. Then the Reservations that you want to have will save without any issues. Crazy!
Tuesday, July 18, 2017 10:36 PM
This was the solution for me. I was trying to create a reservation, but the MAC was already being used in another reservation for another IP. Deleting the old reservation allowed me to make the new reservation.