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Sunday, September 29, 2013

Cisco IOS DHCP reservation

Cisco IOS DHCP basic configuration:

ip dhcp excluded-address
ip dhcp pool LAN
 import all
 domain-name network.local
 lease 7

network is with .1 as default router and 2 DNS servers.

now let's configure reservation for my iPad:

ip dhcp pool iPAD2
 client-identifier 0164.a6c2.f3fc.11
 client-name iPAD2

I reserved IP for MAC address 64a6.c2f3.fc11, which in this case is my iPad MAC address, note that a leading 01 comes to notate that this is an Ethernet media. 

So for every device you would like to do a DHCP reservation create a new pool using his MAC address along with the leading 01. Don't forget to reserve an IP which is in the exclude range.

the following configuration will work almost for every type of device but yesterday i noticed it doesn't work with my Linux machine (CentOS 5.9)?!

after digging a while i found the solution:

ip dhcp pool CENTOS
 hardware-address 0040.c3a4.adf5
 client-name CENTOS

note that this time no leading 01 is needed, only the MAC address of the NIC.


  1. For this you can create specific DHCP pools for the each client and specify their mac address like below.
    ip dhcp pool Client1


    hardware-address xxxx.xxxx.xxxx

    Silvester Norman

    Change MAC Address

  2. Hi Norman,

    Hardware-address is used for Bootp while client-identifier is used for DHCP.