How to block MAC addresses using DHCP or other software

Hi guys
How can I block specific MAC addresses connecting to our network using DHCP (Win Server 2008 R2) or other free software?
Cheers
Troy
P3adminAsked:
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m_walkerConnect With a Mentor Commented:
depending on the size of you network and number of hosts you support, you switchs could support mac filtering (or port level mac lists).  

DHCP wont help alot.  While you could add a static mapping for every host in your network, the other computer could simply set their own ip in your range.

Keep in mind that if you servers are on different "routed" networks/vlans to your computers, then the mac address of the remote computer want make it to the server, so server/host level mac filters will only work if all computers are on the same network (layer2) segment.
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ActiveDirectorymanCommented:
check this article out:

Windows Server 2008 R2: Enable and Configure MAC Address Filtering

http://technet.microsoft.com/en-us/magazine/ff521761.aspx
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P3adminAuthor Commented:
We only have around 100 computers so its not a huge network
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P3adminAuthor Commented:
Hi m_Walker.

Have gone to your link and followed the instructions but cannot find the filter tab as per step 2. This applies to 2008 R2?

Cheers
Troy
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m_walkerConnect With a Mentor Commented:
If you can so it at the switch level, then it should only check as the port comes up (once) then keep the port open unitl the port goes down.  this way the overhead should have less impact on performance.  If done at the server level, each packet would need to be checked so whould have a bigger impact (that you may or may not notice).

Depending on the switchs in play, you could also look at 802.1x and the use of a radius server.  It is more work to setup and understand, but can work.
In an 802.1x network you setup a certificate server on your windows server.  the server will then issue computer certificates (ssl) to each client computer that is in the domain.  (so new computers should be setup on a trusted port with no 802.1x.)  On the switch each port in your untrusted areas, is set to only open when a valid certificate is provided from the client computer.  With the correct setup on the client computer the computer will open the port prior to getting the user to log on to the domain.

Just an optio, but is harder to setup and get right and can cause issues with things like ghost.
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m_walkerConnect With a Mentor Commented:
The link was from ActiveDirectoryman: not me.  So make sure the credits go the right way :)
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ActiveDirectorymanCommented:

Check this out sir:


Distribute DHCP Leases Based on MAC Address  -This does appy to 2008 r2

http://technet.microsoft.com/en-us/library/dd759190.aspx
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P3adminAuthor Commented:
Guys your gonna wanna kill me but it is a 2003 DHCP server.... :S
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Craig BeckConnect With a Mentor Commented:
Server 2003 does not have this kind of native functionality.

The best way to do this would be with a MAC ACL on your switches if they support this.  Otherwise you're pretty much stuck!
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ActiveDirectorymanConnect With a Mentor Commented:

Actually there is a way to enable it on server 2003.

check out this article:

mac address filtering server 2003 and 2008
http://www.petri.co.il/filter-mac-address-windows-server-2008-dhcp-server-callout-dll.htm

mac address filtering on server 2003 and 2008
http://blogs.technet.com/b/teamdhcp/archive/2007/10/03/dhcp-server-callout-dll-for-mac-address-based-filtering.aspx
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m_walkerConnect With a Mentor Commented:
While not an answer to your question as such, your request contained
"...block specific MAC addresses connecting to our network using DHCP..."
I can think of how DHCP would Block access to your network.  While it may not give a computer an IP Address, whats stopping the computer setting a static IP Address.  All the need to do is run a sniffer and look at the arp requests to get an idea of your ip range, then port/ping scan to see whats free and off they go...

What do you really want to achieve ?
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P3adminAuthor Commented:
Just trying to block a few computers that are bought into the building from connecting to resources. Nothing to incidous :)
I found a good link for the DHCPservercallout that had a live link to the downloadable executable
http://blogs.technet.com/b/teamdhcp/archive/2007/10/03/dhcp-server-callout-dll-for-mac-address-based-filtering.aspx
Thanks all for your help on this :)
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m_walkerCommented:
OK. No probs.
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