OPNsense Forum

English Forums => High availability => Topic started by: GreenMatter on March 16, 2026, 01:44:55 PM

Title: CARP VIP link local vs IPv6 communication
Post by: GreenMatter on March 16, 2026, 01:44:55 PM
I'm not able to set CARP VIPs for link local addresses (https://docs.opnsense.org/manual/how-tos/carp.html#setup-virtual-ipv6-link-local-address) to make IPv6 communication flowing. RA announces current, physical link local ipv6 address as router which is different than CARP VIP. I've tried setting fe80::/64 and fe80::1/64  as CARP VIP without any luck...

But as I use tunnelbroker I can't use my ipv4 WAN interface to set up CARP VIP (https://docs.opnsense.org/manual/how-tos/carp.html#setup-virtual-ipv6-global-unicast-address) and I think this should have been my GIF interface...(?) And if I set next hop, either tunnel remote or local address as CARP VIP address, VIP remains as disabled...

How to set it up properly?
Title: Re: CARP VIP link local vs IPv6 communication
Post by: Patrick M. Hausen on March 16, 2026, 02:35:12 PM
fe80::/64 is not a valid address but fe80::1/64 should be fine. I use fe80::<VLAN ID>/64 everywhere.

Please show a screenshot of

- the interface configuration of both units
- the CARP VIP configuration on the active/master (should propagate to the standby once you do a configuration sync)
Title: Re: CARP VIP link local vs IPv6 communication
Post by: GreenMatter on March 16, 2026, 08:22:41 PM
Quote from: Patrick M. Hausen on Today at 02:35:12 PM- the interface configuration of both units
- the CARP VIP configuration on the active/master
So, I adjusted local link addresses - as per your advice to make sure they are different

I couldn't attached screenshots here as limit is only 250 kB (?)
Link to listed below screenshots: https://imgur.com/a/r9RSFma
Master interface: 
Backup interface:
CARP VIP global (I had multicast, same issue, so I tried unicast)
CARP VIP local:
(https://imgur.com/a/r9RSFma)

VHID groups are fine, initially I synchronised CARP VIPs, later I changed them to unicast.
So, where's mistake???
Title: Re: CARP VIP link local vs IPv6 communication
Post by: Patrick M. Hausen on March 16, 2026, 09:00:09 PM
I block so called image hosting sites, sorry.

This works.

Interface configuration on the primary node:

(https://forum.opnsense.org/index.php?action=dlattach;attach=53136;image)

CARP VIP:

(https://forum.opnsense.org/index.php?action=dlattach;attach=53134;image)

Radvd config:

(https://forum.opnsense.org/index.php?action=dlattach;attach=53138;image)

HTH,
Patrick