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Brad
Asked: 2011-07-26 08:48:16 +0800 CST

Microsoft DHCP Known and Unknown Clients

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With ISC DHCPd under Linux, I can define separate pools for "known" and "unknown" clients, like this:

subnet 10.0.0.0 netmask 255.255.255.0 {
    option routers 10.0.0.254;
# Unknown clients get this pool.
    pool {
        option domain-name-servers 10.0.0.254;
        max-lease-time 300;
        range 10.0.0.100 10.0.0.250;
        allow unknown-clients;
    }
# Known clients get this pool.
    pool {
        option domain-name-servers 10.0.0.251, 10.0.0.252;
        max-lease-time 28800;
        range 10.0.0.5 10.0.0.99;
        deny unknown-clients;
    }
}

host SomeHost1 { hardware ethernet 00:0F:1F:BC:A0:B9 ; }

By not specifying an IP for the host, SomeHost1, the DHCP server figures it out. This is important to me, as I have a DHCP server configured to support several VLANs (with DHCP relay on the layer-3 switches).

How can I use such a configuration with Microsoft's DHCP server under Server 2008 R2?

This is also important as some clients may move from one VLAN to another (if they used wireless and went to another building for example). I cannot simply make reservations for each MAC, as then it would no longer be valid if they moved to a different VLAN.

dhcp windows-server-2008-r2 dhcp-server

1 Answers

  1. "The unknown-clients flag is used to tell dhcpd whether or not to dynamically assign addresses to unknown clients. Dynamic address assignment to unknown clients is allowed by default. An unknown client is simply a client that has no host declaration." - http://www.linuxmanpages.com/man5/dhcpd.conf.5.php

    In Windows DHCP server, this concept is called Classes: http://technet.microsoft.com/en-us/library/dd759232.aspx http://thelazyadmin.com/blogs/thelazyadmin/archive/2007/02/08/DHCP-User-Classes.aspx

    Does this work for you?

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