From d1043f1da6bf35b5365d395f29e207cea0bbffc3 Mon Sep 17 00:00:00 2001 From: Maurice Walker Date: Fri, 15 Sep 2023 18:05:55 +0200 Subject: [PATCH] DHCPv6: document downstream prefix delegation --- source/manual/dhcp.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/source/manual/dhcp.rst b/source/manual/dhcp.rst index 7e61db05..6264fab7 100644 --- a/source/manual/dhcp.rst +++ b/source/manual/dhcp.rst @@ -55,6 +55,12 @@ create static assignments based on the clients unique DHCP identifier (`DUID ` are properly configured before debugging DHCPv6 issues, these two daemons depend on eachother. +If a Prefix Delegation Range is specified, downstream routers may request prefixes (IA_PD). Routing a delegated prefix to a downstream +router requires OPNsense to be aware of the router's IPv6 WAN address. This can be achieved in two ways: + +* **Dynamic DHCPv6 address lease**: If an address range is specified in the DHCPv6 service settings and the downstream router requests both an address (IA_NA) and prefix (IA_PD), the prefix will be routed to the leased address. +* **Static mapping**: If the DUID of an active prefix lease matches the DUID of a DHCPv6 static mapping, the delegated prefix will be unconditionally routed to the static mapping's IPv6 address. The DHCPv6 service doesn't have to be configured with an address range and the downstream router doesn't have to request an address. The address in the static mapping may be a GUA, ULA or link-local address. This allows downstream prefix delegation to routers which only request a prefix, not an address. + ------------------------- Advanced settings -------------------------