In principle, the DHCP server and client must be on the same network; this section summarizes how to place the DHCP server.

Enable DHCP Relay Agent on Cisco routers (Cisco IOS). This allows a single DHCP server to support DHCP clients on multiple networks.

In principle, the DHCP server and DHCP clients must be connected on the same network. The DHCP Relay Agent is the function to avoid this restriction.
This section explains how the DHCP Relay Agent works and the configuration commands on a Cisco router (Cisco IOS).

You can use a Cisco router as a DHCP server to distribute IP addresses to DHCP clients.This section describes the configuration and verification commands to make a Cisco router (Cisco IOS) act as a DHCP server.