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I'm using a cable connection from Road Runner/Time Warner. I'm planning to buy out a new Cisco cable modem. I would like to know that how to configure NAT on cable modem? Any one knows how can i do so? Kindly provide me the correct steps for doing so. Any help you can provide would be greatly appreciated. Thanks.
Network Address Translation (NAT) is used to translate IP addresses from one network into IP addresses for another network. Network Address Translation (NAT) replaces IP addresses within a packet with different IP addresses. NAT is performed by a router and is commonly used to translate private IP addresses used in homes and businesses into the public IP addresses that are used on the Internet. NAT is useful for conserving IP addresses and connecting a private network using unregistered addresses to a public network like the Internet.
NAT is used on the cable modem when the CPE devices that use an unregistered address need to connect to the Internet. When configuring NAT, there are a number of terms and concepts you need to know. For example: the difference between inside local, inside global, outside local, outside global, NAT vs. PAT, and “NAT overload.” Cable modems also connect to the Cisco Customer Premises Equipment (CPE) like PCs over the LAN interface. Cable modems like the uBR900 series devices are used to provide Internet access to users through a cable network by connecting to a Cable Modem Termination System (CMTS) device.
Try to enter "ipconfig /renew" in the run command of the start window. When configuring PAT, a NAT pool has to be defined with the valid addresses made available by the provider. When configuring PAT on the cable modem, the unregistered addresses that belong to the CPE devices on the LAN interface are translated to the IP address, which is assigned to the cable interface provided by the service provider through DHCP. Use Port Address Translation (PAT) to bind the single valid address to the various unregistered addresses, which are used by the CPE devices. The DHCP server can run either on the CMTS itself or on another device that can be accessed by the CMTS.
With this home network setup we connect all Ethernet cables (PC and ADSL) to a hub or switch. You will need the uplink connector to connect the ADSL connector. Cable Modem services from NTL are very well and good, but they do have one or two limiting factors. The hub or switch can be any model UTP based hub preferably with a uplink/MDI crossed connector. The first is that you are furnished with only one IP address, which implies that you can only use one PC with your Cable Modem.The easiest way to determine that you have dynamic NAT configured in your cable modem is by searching for this command in the configuration of the cable modem:Quote:
ip nat inside source list 100 interface cable-modem0 overload
You should note that you will have to configure the router’s primary Ethernet IP as the default gateway for all PCs in the NAT network. Before configuring NAT, enable routing on the cable modem by issuing the no cable-modem compliant bridge command under the cable interface. To automatically get the address from the provider and use it in the NAT pool, the NAT pool can be configured manually or the cable modems can be configured as a DHCP proxy agent. Remove any bridge groups under the cable and LAN interfaces by issuing the no bridge-group commands.