What is DHCP relay agent?

What is DHCP relay agent?

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.

How do I make my router a DHCP relay agent?

To configure a router’s interface as a DHCP relay agent, use the following command in interface configuration mode….Configuring DHCP relay agents.

Router Interface Connected local subnet
Router1 Fa0/1
Router2 Fa0/0
Router2 Fa0/1

What is DHCP relay VLAN?

DHCP VLAN Relay can manually designate an L3 interface for all the VLANs as the default relay agent interface. All the DHCP packets can be forwarded through this interface so that the clients can get IP addresses from the DHCP server.

What is DHCP relay and how it works?

The DHCP relay agent is any TCP/IP host which is used to forward requests and replies between the DHCP server and client when the server is present on a different network. Relay agents receive DHCP messages and then generate a new DHCP message to send out on another INTERFACE.

What is a DHCP relay address?

The IP address of the primary DHCP relay agent receiving a client request packet is automatically added to the packet, and is identified as the giaddr (gateway interface address.) This is the IP address of the VLAN on which the request packet was received from the client.

What is the difference between DHCP server and DHCP relay?

A DHCP relay agent sits between a DHCP server and DHCP clients and allows the DHCP clients to obtain IP addresses from the DHCP server that is not configured on the same LAN.

Can a switch be a DHCP relay agent?

You can configure the DHCP option 82 feature in two topologies: The switch functions as a relay agent when the DHCP clients or the DHCP server is connected to the switch through a Layer 3 interface.

How does DHCP work with VLANs?

DHCP uses the IP address of a VLAN to determine the pool from which it should provide an IP configuration. To assign an IP address to the VLAN, use the following commands. Assign an IP address to each VLAN from the reserved IP address of the corresponding DHCP pool.

Where is DHCP relay agent configure?

Configure DHCP Relay

  • Select a trusted, optional, or custom interface and click Configure.
  • From the drop-down list at the bottom of the page, select Use DHCP Relay.
  • In the DHCP Server text box, type the IP address of a DHCP server and click Add.

What is a relay agent and when it is needed?

How do I test a DHCP relay?

Viewing the DHCP relay setting Use the show config command (or show running for the running-config file) to display the current DHCP relay setting. NOTE: The DHCP relay and hop count increment settings appear in the show config command output only if the non-default values are configured.

Which port does the relay agent use when it sends DHCP information back to the client?

Answer. DHCP messages from a client to a server are sent to the ‘DHCP server’ port (67), and DHCP messages from a server to a client are sent to the ‘DHCP client’ port (68).

Is DHCP relay and IP Helper the same?

Re: DHCP relay and ip-helper- what’s the different? the dhcp-relay command in global config is to enable or disable the use of ip-helper to relay DHCP packets. if you disable dhcp-relay, the ip-helper command will not relay DHCP anymore, but still be able to be used as UDP forwarder for other protocols.

What is DHCP relay on a switch?

DHCP Interface Relay: With DHCP Interface Relay enabled, when the switch receives the DHCP request packets, it will forward the packets through the Layer 3 gateway to the DHCP server, and forward the DHCP offers from the DHCP server to the corresponding subnets afterwards.

Does VLAN require DHCP?

Each VLAN is a broadcast domain, so essentially you have to put a DHCP server on each VLAN.