PPPoE daemon selects wrong interface

kolpinkb

I'm experiencing a strange issue where the pppoe daemon selects/reports the wrong interface for establishing an IPv6 connection.

Background:

1x Intel i350-T4V2 card
Mac addresses of PHY:
xx:xx:xx:xx:xx:04 (WAN)
xx:xx:xx:xx:xx:05 (LAN)
xx:xx:xx:xx:xx:06 (OPT1)
xx:xx:xx:xx:xx:07 (OPT2)

During bootup, manually disconnecting/reconnecting pppoe session results in the unexpected behaviour. Also, sometimes when the ISP drops the pppoe session for load balancing purposes the pppoe daemon will sometimes select the improper interface. Sometimes the :04 interfaces is chosen and other times the :05. This behaviour wasn't present in pfSense 2.4.2.

The result of this instability is that sometimes the WAN wont receive and IPv6 address and thus no outbound/inbound IPv6 connectivity is possible.

Note: One would expect the xx:xx:xx:xx:xx:04 interface to be chosen every time. 0_1545050414760_pppd error 1.png

The defect appears similar to one reported a number of years ago (https://forum.netgate.com/topic/59789/ipv6-over-pppoe-wrong-default-gateway) but without a developer looking into the code there is not way for me to tell.