DHCPv6 Multicast Addresses and UDP
Ports
The relay agent uses specific multicast addresses and UDP ports for the DHCPv6 functionality.
- Multicast addresses
- All_DHCP_Relay_Agents_and_Servers (FF02::1:2) is a link-scoped multicast
address used by the client to communicate with neighboring (for example,
on-link) relay agents and servers. All servers and relay agents are members of
this multicast group.
- All_DHCP_Servers (FF05::1:3) is a site-scoped multicast address used by
the relay agent to communicate with servers, either because the relay agent
wants to send messages to all servers or because it does not know the unicast
addresses of the servers. To use this address, a relay agent must have an
address of sufficient scope to be reachable by the servers. All servers in the
site are members of this multicast group.
- UDP ports
- The relay agent listens on UDP ports 546 and 547 for packets sent by clients and
servers. The relayed packets use the source port 547.
