Help Changing DNS on Cisco 4321

[alingerfelt]

We have a Cisco 4321 that provides DHCP and DNS to our entire network.  

I would like to update the dns settings (from internal servers) to Open DNS.  I can connect to the 4321 with telnet.  Can someone walk me through how to make this change using telnet in my Windows command prompt?

I'm asking for help because I've been asking our DFW area support rep for a month to get this done and they haven't.  

To be safe, I'd like to somehow first save a backup or copy of our current configuration.

[balaji.bandi]

yes take the config back up - also you need to provide the show run config here to suggest best :

if your router offering DHCP Server below example to change DNS for LAN IP subnet :

(config)#ip dhcp pool MyDHCP
(dhcp-config)#network 192.168.0.0 255.255.255.0
(dhcp-config)#default-router 192.168.0.1
(dhcp-config)#dns-server x.x.x.x (change this to your OpenDNS IP)

[balaji.bandi]

If you looking to change DHCP Lan DNS the change as below here you need to change as below :

ip dhcp pool DATA

no   dns-server 192.168.123.199 192.168.123.200

dns-server x.x.x.x (open DNS Server IP)

   lease 0 8

after changing : restart IP or  renew dhcp lease, 

on windows ipconfig /all ( you see new DNS entry) - then browse any site see if that works ?

[alingerfelt]

Additional follow up question:

How can I also remove uneccessary ip hosts or dhcp excluded addresses from the configuration?

[alingerfelt]

Got it!  Now how do I successfully save this running config to the startup config, in case of a power outage or reboot?

[balaji.bandi]

glad you able to figure it out, how to remove the excluded IP, we mark it as resolved all good.