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DHCP Server Callout DLL for MAC Address based filtering - MAC Address List File Format

DHCP Server Callout DLL for MAC Address based filtering - MAC Address List File Format

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Looking at the problem in configuring Mac Address List File while configuring callout DLL for Mac Address based filtering, here are some detailed tips which will help you in verifying your configuration with one below...

·         File should contain action followed by MAC address list as show in below format. There is stringent check on the format and hence it needs to be strictly followed including braces etc.





       ·         First line in the file should specify the action. Action can be either ALLOW or DENY. Please note the braces around action.

o   When action is specified as ALLOW, all requests from MAC address present in this list will be served by dhcp servers. All requests originating from MAC address not present in this list will be ignored.

o   When action is specified as DENY, all request from MAC address present in the list will be ignored by dhcp servers. All requests from MAC addresses not present in this list will be severed by dhcp server.

o   Only one action out of ALLOW or DENY can be specified in MAC Address List File

·         MAC address should be specified in format XXXXXXXXXXXX (where X can be hex digit 0 - F).There should not any delimiter such as -,  : in MAC address.  Each MAC address should be specified in separate line.

·         If there is any error in MAC Address List File, it will be logged into CalloutErrorLogFile or default error log file.  Following is expected behavior of dll in cases of errors

o   If the action is not specified correctly, then dhcp server will function as if there is no callout dll i.e. none of the requests will be ignored. Error for the same will be logged in error log file.

o   If one or more MAC addresses are not specified correctly, then in this case those MAC address entries will be ignored. Error for the same will be logged in error log file.


Govind [MSFT]


  • should i leave the MacFilterCallout.dll and SetupDHCPMacFilter.rtf in the default folder are should i move them to the folder i create on the root of my C drive

  • Hey,

    You can move the SetupDHCPMacFilter.rtf file anywhere. However You shouldn't be moving the location of the MacFilterCallout.dll from the location which you have specified in the registry while configuring the callout dll.


    Raunak Pandya

    DHCP Server Team

  • I need insert comments on my file MAClist.txt where stay all of my mac address.

    I want to do this for identify all of my MACs.



    000a0c0d1254         'machine01

    000d0c4a6723         'machine02

    Is there any option to do this?

  • Hey Bruno,

    Currently there is no option in this callout dll to insert comments.


    Raunak Pandya

    DHCP Server Team

  • I noticed that the machines that I am trying to get a ip from the DHCP server are Vista Buisness.  Is there anything going on with this not working on Vista Business

  • Has support for Server 2003 x64 been added yet?  If not, I will have to use another DHCP server as the functionality provided by the callout DLL is required for my application.  Thanks!

    Matthew Monacelli

  • Matthew,

      We will be releasing the x64 version, in a few weeks.     Stay tuned via the blog.



    Team DHCP

  • Michael VanDusen,

      The DHCP Server does not specifically allow or deny based on the Operating system of the client.    Check that the MAC address of the client is in the filter file.


    Team DHCP

  • Do you have to also enter DHCP addresses you wich to ALLOW or just the ones you want to DENY.

  • Hey Jim,

    The tool works in two modes, ALLOW/DENY depending on the first line in the MACList.txt file. If its working in ALLOW mode, the MAC addresses in the MACList.txt file will be allowed and rest denied. Similarly if in DENY mode, MAC Addresses in MACList.txt will be denied and rest all will be allowed.

    Raunak Pandya

    DHCP Server Team

  • this dll setting is neither working nor generating any error on my windows server 2003 64 bit platform while i have checked all the settings

  • Shadab,

      You will require a different DLL (currently in testing) that supports 64 bit OSs.

      You can contact me at msnetworkteam_AT_live_DOT_com for an early version of this dll.


  • I just installed this tool, and I am really happy that this tool. Will post more when the user start using in the am.


  • This addon is great, I would love to see wildcard support though - so I could stop the random students iPhone from hitting us :)

  • this tool works great with one exception.  We have it set to a allow list of MAC addresses.  The problem that we have comes with wireless access points (LinkSys Routers). The MAC for the laptops are in the allow list but the DHCP will not assign an ip address.  I have even inserted the MAC for the wireless access router but still no luck.  Any suggestions? (I know the wireless SSID and key are correct because when a static ip is assigned in the wireless connection config the computer connects to the network)

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