Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

DHCP to Private NAT

Failed the CCNA once already, got whomped by the NAT lab and now looking to get a NAT lab running at home to work on it with.

I have a 3640, a 3550 and a 2950 to work with. I also have cable modem service with a dynamic IP assigned ua DHCP.

Is it possible to put port eth0/0 on the 3640 to get it's ip from dhcp and port eth0/1 to assign private ips to my network and pat between them?


Re: DHCP to Private NAT

Cable modems are used to provide Internet access to users through a cable network by connecting to a Cable Modem Termination System device. The cable modems also connect to the Customer Premises Equipment, such as the PC over the LAN interface. Like uBR900 series cable modem can operate in either bridging or routing mode. NAT is used on the cable modem when the CPE devices that use an unregistered address need to connect to the Internet. This is done by using the valid address provided by the service provider. Use Port Address Translation (PAT) to bind the single valid address to the various unregistered addresses, which are used by the CPE devices.

Following URL which help you for the configuration for the DHCP nat on the cable modems. :