This is a stateless DHCPv6 relay for Linux.
dhcp6relay [-v]
[-i <input-interface>]...
[-o <output-interface>]...
dhcp6relay listens for DHCPv6 clients on the named input interfaces and relays their requests to the DHCPv6 servers on the output interfaces.
Eventually, successful clients will switch to communicating with the servers using IPv6 unicast packets, which do not need relaying.
If dhcp6relay receives a SIGHUP signal, then it will re-open the interfaces, refreshing the link-local addresses and interface indicies that it had found before.
The -v option increases verbosity.
Because dhcp6relay uses Linux's AF_PACKET sockets, it will not subject to
firewall rules. Instead, it uses the following filter processes.
A DHCPv6 client packet is only accepted on an input interface for relaying when it has:
- destination address ff02::1:2
- protocol UDP
- destination port 547
- message-type is not one of ADVERTISE(2), REPLY(7), RECONFIGURE(10), or RELAY-REPL(13).
A DHCPv6 server reply packet from an output interface is only relayed back to a client if it has:
- a link-local scoped source address
- a link-local scoped dest address
- protocol UDP
- destination port 547
- message-type RELAY-REPLY(13)
- an interface-ID option matching a listed input-interface
- link-address field set to ::