Posted in CCIE R&S, IP Services on Jul 22nd, 2009
The DHCP Information option (Option 82) is commonly used in metro or large enterprise deployments to provide additional information on “physical attachment” of the client. Option 82 is supposed to be used in distributed DHCP server/relay environment, where relays insert additional information to identify the client’s point of attachment.... [Read the rest of this entry -->]
Posted in CCIE R&S, IP Services on May 3rd, 2009
A question on GroupStudy gave me an idea for the short post dedicated to explaining the use of DHCP “import all” command. The command first appeared in IOS 12.2T. It allows importing certain DHCP information learned from some external source, such as another DHCP server. This is helpful in reducing the amount of configuration needed in large hub-and-spoke networks, where spokes use centralized servers (e.g. WINS, DNS, TFTP). Instead of configuring the repetitive settings in every spoke router, you may import them by requesting an IP address for the router via DHCP. More than that, any change in central configuration could be easily imported in the remote routers, using DHCP address refresh. Here is how it works:... [Read the rest of this entry -->]
