What is a DHCP relay?

A DHCP relay agent is a host or router that forwards DHCP packets between clients and servers. Network administrators can use the DHCP Relay service of the SD-WAN appliances to relay requests and replies between local DHCP Clients and a remote DHCP Server.

What is Cisco DHCP relay?

A DHCP relay agent is any host that forwards DHCP packets between clients and servers. Relay agents are used to forward requests and replies between clients and servers when they are not on the same physical subnet.

Can a switch be a DHCP relay?

The routing switch can operate as a DHCP relay agent to enable communication between a client and a DHCP server on a different subnet. Without Option 82, DHCP operation modifies client IP address request packets to the extent needed to forward the packets to a DHCP server.

What is DHCP relay agent command?

A DHCP relay agent uses “ip helper-address” command to indicate the DHCP server’s IP address. It will insert the IP address of the interface which has that command configured into the gateway IP address field of DHCP packet to let DHCP server know which IP address range should be used to allocate.

What is the DHCP relay agent on a Cisco router?

Cisco routers running Cisco IOS software include Dynamic Host Configuration Protocol(DHCP) server and relay agent software. A DHCP relay agent is any host that forwards DHCP packets between clients and servers. This module describes the concepts and tasks needed to configure the Cisco IOS DHCP relay agent.

How do I configure a trusted interface for DHCP relay information?

• You can configure an individual interface as a trusted source of the DHCP relay information option by using the ip dhcp relay information trusted interface configuration mode command. Returns to privileged EXEC mode. (Optional) Displays all interfaces configured to be a trusted source for the DHCP relay information option.

What are the different types of DHCP relay information commands?

The following commands were introduced by this feature: ip dhcp relay information check-reply, ip dhcp relay information option-insert, and ip dhcp relay information policy-action This feature enables an ISP to add a unique identifier to the subscriber-identifier suboption of the relay agent information option.

How to forward UDP broadcasts to a DHCP server using helper address?

The DHCP relay agent sends the local broadcast, via IP unicast, to the DHCP server address 172.16.1.2 specified by the ip helper-address interface configuration command. Figure 1 Forwarding UDP Broadcasts to a DHCP Server Using a Helper Address Enables privileged EXEC mode. • Enter your password if prompted. Router# configure terminal