What is a DHCP relay server?
A DHCP relay agent is a host or router that forwards DHCP packets between clients and servers. It allows local hosts to acquire dynamic IP addresses from the remote DHCP Server. Relay agent receives DHCP messages and generates a new DHCP message to send out on another interface.
How DHCP relay works step by step?
DHCP relay agent is any TCP/IP host which is used to forward request and replies between DHCP server and client when the server is present on the different network. Relay agents receive DHCP messages and then generate a new DHCP message to send out on another INTERFACE.
How do I add a DHCP relay?
- Select DHCP Relay. Select. Network. DHCP. DHCP Relay. .
- Specify the IP address of each DHCP server with which the DHCP relay agent will communicate. In the. Interface. field, select from the drop-down the interface you want to be the DHCP relay agent. Select either. IPv4. or. IPv6.
- Commit the configuration. Click. OK. and. Commit. .
What is IP DHCP relay information option?
ip dhcp relay information option Enables the system to insert the DHCP relay agent information option (option-82 field) in forwarded BOOTREQUEST messages to a DHCP server. This function is disabled by default. Configures an interface and enters interface configuration mode.
Why do we need a DHCP relay?
As shown in Figure 1 – (b), enabling the DHCP relay agent function in the router allows DHCP messages to be exchanged between a DHCP client and DHCP server residing on different subnets. The core function of this DHCP relay agent is to convert a broadcast DHCP packet into a unicast one, and forward it to a DHCP server.
Why DHCP failed apipa is being used?
APIPA stands for Automatic Private IP Addressing, and is a feature on the windows or some other operating systems to self-configure the IP address and Subnet mask if DHCP server isn’t reachable. If you are seeing such error message on your screen of the PC, that means something is wrong with the router DHCP.
What is the purpose of DHCP relay agent?
The DHCP relay agent operates as the interface between DHCP clients and the server. The DHCP Relay Agent relays DHCP messages between DHCP clients and DHCP servers on different IP networks.
Which is the server address for DHCP relay?
The relay agent unicasts the messages to the server address, in this case 172.16.1.2 (which is specified by the helper address in the relay profile). Figure 1.
How does router B work as a DHCP relay agent?
Acting as a DHCP relay agent, Router B picks up the broadcast, changes the destination address to the DHCP server’s address and sends the message out on another interface.
What does the DHCP Link Selection sub-option do?
The Relay Agent Link Selection sub-option allows a DHCP Relay Agent to specify an IP subnet from which the DHCP server should assign IP addresses and options. Typically, DHCP relay agents rely on the Gateway IP Address (GIADDR) field to communicate with DHCP servers.
How does the DHCP relay agent increase the hop count?
During this process, the DHCP relay agent increases the hop count by one before forwarding the DHCP message to the server. A DHCP server includes the hop count from the DHCP request that it receives in the response that it returns to the client. DHCP packet forwarding
