pfSense

pfSense successfully hands out PDs, but does not install a route for them. This effectively causes traffic to black hole at the pfSense host, and not return to LAN hosts.

Issue occurred after upgrading to 23.05-RELEASE, and wasn't present in 23.01-RELEASE.

Scenario: pfSense receives /56 from ISP (WAN), and is configured within DHCPv6 to hand out /60s via LAN interface.

PD issuance:

/var/log/dhcpd.log:May 24 17:10:30 router dhcpd[34360]: Picking pool prefix 2600:xxxx:4f0::/60
/var/log/dhcpd.log:May 24 17:10:30 router dhcpd[34360]: Advertise PD: address 2600:xxxx:4f0::/60 to client with duid xxxx iaid = 1 valid for 7200 seconds

Post PD routing table, note lack of route for /60:

23.05-RELEASE][xxxx@router]/home/xxxx: netstat -6rn | grep em1
2600:xxxx:400::/64           link#2                        U           em1
...

Rolled back to 23.01-RELEASE, note existence of /60:

[23.01-RELEASE][xxxx@router]/home/xxxx: netstat -6rn | grep em1
2600:xxxx:400::/64           link#2                        U           em1
2600:xxxx:4f0::/60           2600:xxxx:35d5    UGS         em1
...

Thread previously opened several weeks ago per reporting guidelines: https://forum.netgate.com/topic/180346/dhcpv6-pd-not-installing-route-after-23-05-release-upgrade