Chapter 8. IP address assignment by using Dynamic Host Configuration Protocol
In the last chapter, you got your two virtual LANs (VLANs) talking to each other by coming up with two IP subnets and configuring two switched virtual interfaces (SVIs), one for each VLAN. Configuring an SVI for a VLAN is something you typically have to do only once per VLAN because each subnet needs only one default gateway to reach other subnets.
But when it comes to devices within a VLAN—computers, printers, security systems, and so on—manually assigning IP addresses one by one as you did in the last chapter is too tedious and prone to error. You need a way to automatically assign IP addresses from a subnet to devices in any given VLAN.
Dynamic Host Configuration Protocol (DHCP) is a service that takes a range of IP addresses from a subnet and automatically assigns them to devices in a VLAN. It can also automatically assign other network parameters, such as the default gateway and Domain Name System (DNS) servers. Many organizations also use DHCP to automatically tell Cisco IP phones which Call Manager server to connect to. Regardless of the application, the goal of DHCP is to save you from ever having to touch the network configuration on a networked device.
In this chapter, you’ll learn how to configure a Cisco switch to automatically assign IP addresses using DHCP. If your organization already has a DHCP server, you’ll learn how to configure your switch to play nicely with it.