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DHCPv4 & DHCPv6 Relay¶
DHCP requests are broadcast traffic. Broadcast traffic is limited to the broadcast domain where it is initiated. To provide DHCP service on a network segment without a DHCP server, use the DHCP relay to forward those requests to a defined server on another segment.
It is not possible to run both a DHCP server and a DHCP Relay at the same time. To enable the DHCP relay, first disable the DHCP server on each interface.
To configure the DHCP Relay:
Disable the DHCP Server on every interface
Navigate to Services > DHCP Relay
Click the tab for the interface to use with DHCP Relay
Configure the options as follows:
- Enable DHCP Relay
- Append circuit ID and agent ID to requests
Check this to add a circuit ID (pfSense® interface number) and the agent ID to the DHCP request. This may be required by the DHCP server on the other side, and can help distinguish where the requests originated.
- Destination Server
A manual entry box to set the target DHCP server
The DHCPv6 Relay function works identically to the DHCP Relay function for IPv4.