jump to navigation

How to fix MAC Address with IP Address on DHCP server. December 9, 2009

Posted by jbanju in LINUX CentOS.

1. Get a MAC Address from Client’s laptop such as  A1:B2:C3:A1:B2:C3

2. Add the MAC Address into the file /etc/dhcpd.conf such as

ddns-update-style interim
ignore client-updates
subnet netmask {
   # The range of IP addresses the server
   # will issue to DHCP enabled PC clients
   # booting up on the network
   # Set the amount of time in seconds that
   # a client may keep the IP address
   default-lease-time 86400
   max-lease-time 86400
   # Set the default gateway to be used by
   # the PC clients
   option routers
   # Don't forward DHCP requests from this
   # NIC interface to any other NIC
   # interfaces
   option ip-forwarding off
   # Set the broadcast address and subnet mask
   # to be used by the DHCP clients
   option broadcast-address
   option subnet-mask
   # Set the NTP server to be used by the
   # DHCP clients
   option ntp-servers
   # Set the DNS server to be used by the
   # DHCP clients
   option domain-name-servers
   # If you specify a WINS server for your Windows clients,
   # you need to include the following option in the dhcpd.conf file:
   option netbios-name-servers
   # You can also assign specific IP addresses based on the clients'
   # ethernet MAC address as follows (Host's name is "laser-printer":
   host user-one {
      hardware ethernet A1:B2:C3:A1:B2:C3
# List an unused interface here
subnet netmask {

3. Check your configuration file is correct :

# /usr/sbin/dhcpd -t -cf /etc/dhcpd.conf

4. Restart your DHCP Service :

# service dhcpd restart

5. Set DHCP relay in your CISCO switch points to your DHCP Server (Assume your IP Address of DHCP Server is

$ conf t
$ conf t > interface vlan 10
$ conf t > ip address
$ conf t > no ip directed-broadcast
$ conf t > ip helper-address
$ conf t > end

6. You can check all IP Addresses which receive from DHCP Server in file /var/lib/dhcp/dhcpd.leases



No comments yet — be the first.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: