DHCRELAY6(8) FreeBSD System Manager's Manual DHCRELAY6(8)
NAME
dhcrelay6 - Dynamic Host Configuration Protocol for IPv6 (DHCPv6) relay
agent
SYNOPSIS
dhcrelay6 [-dlov] [-E enterprise-number] [-I interface-id] [-R remote-id]
-i interface destination ...
DESCRIPTION
The dhcrelay6 utility provides a means for relaying DHCPv6 requests from
a subnet to which no DHCP server is directly connected to one or more
DHCPv6 servers on other subnets.
dhcrelay6 listens for DHCPv6 requests on a given interface. When a query
is received, dhcrelay6 forwards it to the list of DHCP destinations
specified on the command line. When a reply is received, it is sent on
the network from whence the original request came.
The destination might be an address followed by a `%' and an interface
name, or just an interface name (e.g. "2001:db8::1%em0" or "em1"). When
no address is specified, dhcrelay6 will use multicast on the specified
interface.
The options are as follows:
-d Do not daemonize. If this option is specified, dhcrelay6 will
run in the foreground and log to stderr.
-E enterprise-number
Choose the enterprise-number that will be used by the Remote-ID
option (this only has effect when using -R).
-I interface-id
The interface-id relay agent information option value that
dhcrelay6 should use on relayed packets. If this option is not
specified, it will use the interface name by default.
Avoid using this option when using Lightweight DHCPv6 Relay Mode
(layer 2 relay), otherwise dhcrelay6 will always send replies
back to the client interface, which will break networks with
multiple DHCPv6 layer 2 relay agents.
-i interface
The name of the network interface which will receive client
DHCPv6 requests. For layer 3 mode at least one IPv6 local, site
or global address has to be configured on this interface.
-l Use the Lightweight DHCPv6 Relay Agent mode (layer 2 relaying).
-o Add the Interface-ID option. This option is activated by default
when using layer 2 relaying.
-R remote-id
Enable and add the specified Relay Agent remote-id to identify
this relay segment.
-v Debug mode. This option will make dhcrelay6 run in the
foreground, log to stderr and show verbose messages.
EXAMPLES
Relay multicast packets in the current network to a unicast address (the
relay must have a global address in em0):
# dhcrelay6 -i em0 2001:db8::1000%em0
Listen to one subnet and multicast DHCPv6 packets to another (requires at
least link-local addresses):
# dhcrelay6 -i em0 em1
Relay DHCPv6 packets with Interface-ID (option 18) using the input
interface as its content:
# dhcrelay6 -o -i em0 2001:db8::1000%em0
Same thing as before but with a custom Interface-ID:
# dhcrelay6 -o -I "OpenBSD Router 1" -i em0 2001:db8::1000%em0
Use Lightweight DHCPv6 Relay Agent (layer 2 relay) in a bridged or
switched network (no IPv6 address required). Only makes sense when em0
and em1 are configured in a bridge(4), since dhcrelay6 needs to drop the
original DHCPv6 packets and send modified ones with Interface-ID option.
# dhcrelay6 -l -i em0 em1
Identify a segment using Lightweight DHCPv6 Relay Agent (layer 2 relay)
with a Remote-ID (option 37) instead of an Interface-ID:
# dhcrelay6 -l -R "OpenBSD Router A" -i em0 em1
SEE ALSO
bridge(4), dhcrelay(8)
STANDARDS
R. Droms, J. Bound, B. Volz, T. Lemon, C. Perkins, and M. Carney, Dynamic
Host Configuration Protocol for IPv6 (DHCPv6), RFC 3315, July 2003.
B. Volz, Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Relay
Agent Remote-ID Option, RFC 4649, August 2006.
D. Miles, S. Ooghe, W. Dec, S. Krishnan, and A. Kavanagh, Lightweight
DHCPv6 Relay Agent, RFC 6221, May 2011.
AUTHORS
dhcrelay(8) was written by Ted Lemon <
[email protected]> and reworked by
Henning Brauer <
[email protected]>.
IPv6 support was implemented by Rafael Zalamena <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 March 2, 2023 FreeBSD 14.1-RELEASE-p8