I have a setup in a datacenter running 2 CCR1036 in an active/standby setup.
Both CCRs have identical configuration and use VRRP for the failover.
This setup has been in use for over 4 years (an I suspect the problem I will describe is that old too)
Everything works perfectly fine except IPv6.
When CCR1 is master (which is pretty much always) IPv6 is almost unusable.
It will stop routing traffic for random IPs. Clients cannot even ping the router. This will either happen for a few seconds on a single IP or for hours or days for another IP. It totally random (both the timing and the affected IPs), I haven't found any patterns whatsoever as to what it's causing this and to which IPs.
On the other hand, when i failover to CCR2 (which remember, it has identical configuration with CCR1), then there is no packet loss to any IP for days (so far).
The IPv6 setup is rather simple.
Both routers do not make use of firewall (connection tracking is completely disabled) and in IPv6 do not have any special config.
We announce via BGP our /48 and have various /64s on various VLANs behind the CCRs and a some static routes for some /128 and /64.
IPv4 traffic works perfectly fine on both CCRs for years without any issue.
I tried resetting the configuration on CCR1 and reconfigured everything from scratch using an export (not restoring a full backup).
Nothing changed. The problem is exactly the same.
At this point the only thing I can think of is that the ROS installation on CCR1 is somehow bad and causes these issues.
The next thing to try would be to do a netinstall.
I tried doing this remotely (using a windows VM at the datacenter and bridging its network interface to port 8 of the CCR) but no matter how many attempts it would never show up in netinstall. Also tried on port1 but to no avail.
So I'll have to go to the datacenter myself to be able to do a proper netinstall with my laptop connected directly to port8.
My question at this point is, if anyone else has had similar issues and if they found a solution that might save me from the trip to the DC.