WAN_DHCP6 Gateway Stuck Pending

[bimmerdriver]

I changed internet service from VDSL to fibre recently and was reminded there is still a problem with OPNsense not being able to determine the IPV6 gateway address, resulting in the WAN_DHCP6 gateway not working unless the monitor IP address is manually set to the address of the gateway. When my service was upgraded, the IP address was still pointing at the address of the old gateway, which is no longer pingable. I cleared the address and rebooted to see if OPNsense could determine the address and it could not, so again, I had to manually set the address in gateway settings. I still have a pfSense system running and since it upgraded to BSD 14, it's having the same problem.

If there is anything I can do to help determine why this is happening, let me know.

[franco]

Hmm, if I remember correctly the previous ISP only sent router solicitation after successful DHCP (v4) connect but that never goes through because IPv6 connects instantly. Still the same ISP?

Since we can't change the ISP behaviour the way this could be solved would be to start IPv6 only after IPv4 was established. It's not impossible but generally tricky to get the timing right (separate configuration option, IPv4 address check so that dhcp6c is not started beforehand).

Do you have the time to try the development version? Because we did fix another issue with SLAAC registration of router and DNS servers which may or may not be provided by your ISP as well...

https://github.com/opnsense/core/issues/5862


Cheers,
Franco

[bimmerdriver]

I'm with the same ISP. The only difference is gigabit GPON rather than VDSL. The gateway has a different address, but it's still a Nokia, as it was before. This ISP requires the DHCPv6 solicit / advertise, request / reply sequence to take place before the ICMP router solicitation / router advertisement sequence. The router will not respond to RS with RA if a prefix has not been delegated.

The behaviour I'm observing is the same for the release version and the development version. I think it started when BSD was upgraded to version 14. I think it may have something to do with the M and O flags not being set in the RA message.

If you would like to take a look at the system, it can be arranged.

[franco]

Sorry for the delay, I'd like to take another look at the system now with the latest 23.1 release if you already have it.


Cheers,
Franco

[bimmerdriver]

Sorry for the delay on my part. I haven't had much time lately to look at this.

Over the past few days, I updated my test systems to the latest version. The problem is the same for the release version and the development version.

In both cases, unless I manually enter the gateway address, dpinger will report that the gateway is offline. Also, in both cases, the address of the WAN_DHCP6 gateway is reported as ~.

Would you like to test the latest release version or development version? I can provide either.

[franco]

Also sorry, was not in the office since your reply. 23.7-RC1 would be nice.


Cheers,
Franco

[bimmerdriver]

No problem, I've been away also.

I downloaded the most recent iso and did a clean install. The version is 23.7.

I switched to development and did an update. The version is 23.7.r_56. Is that 23.7-RC1?

[franco]

All better than 23.7-RC so I'll take it. :)


Cheers,
Franco

[franco]

I think we finally uncovered the issue. It was an ancient stray source patch that pfSense had from at least a decade ago. We dropped it in 2018 and they seemed to have dropped it this year too.

https://github.com/opnsense/core/issues/6747#issuecomment-1678487672


Cheers,
Franco

[franco]

FWIW: should work now on 23.7.2. Happy to have it confirmed by you as well when you have the time.


Cheers,
Franco

[bimmerdriver]

I'm happy to report that this is fixed!

Thank you.