Setting up DHCP and DNS services on Cisco Routers

In this blog I will explain how to setup a DHCP and DNS server on your Cisco router.

The network subnet is as follows:

Network Address: 192.168.0.0
Subnet Mask: 255.255.255.0
Router: 192.168.0.1
Dynamic Range: 192.168.0.10 - 192.168.0.254
ISP DNS Server: 8.8.8.8
Subnet Domain Name: mylan.local

These commands specify the DNS server and local domain to the router:


ip domain name mylan.local
ip name-server 8.8.8.8

This command enables the Cisco DNS Service

ip dns server

Before we create our DHCP server, we should specify which IP's are not to be assigned. This being 192.168.0.1 to 192.168.0.9

ip dhcp excluded-address 192.168.0.1 192.168.0.9

Now we specify our DHCP Pool:

ip dhcp pool MyLAN
   network 192.168.0.0 255.255.255.0
   default-router 192.168.0.1
   dns-server 192.168.0.1
   domain-name mylan.local
   lease 7
!

You may now wish to assign statically assigned IP addresses to various hosts on your network. You can do this by creating another DHCP pool

ip dhcp pool MyLaptop
   host 192.168.0.10 255.255.255.0
   client-identifier 0100.0430.52c7.88
!

Note: The client identifier is NOT the MAC address of the client. The easiest way to find the client identifier is to connect the machine to the network and wait for it to be assigned an IP by the router.

In enable mode, type in:

show ip dhcp binding

Match the client identifier with the IP address you were dynamically assigned then create your static pool like the one mentioned above.