IPv6 - Router not use it after prefix-update

RouterOS General
1

Hello Forum,

I'm not sure if I've found a bug.
On my RB5009 running ROS 7.25, IPv6 stops working on the router itself after 30 minutes.
I noticed this because a WireGuard VPN that requires IPv6 stopped working.

I connect to my ISP via PPPoE over fiber optic (SFP).
My ISP assigns me a /56 prefix for IPv6.
IPv6 addresses are distributed across the network via SLAAC.
I’ve also set up ULA.
The router is accessible from the Internet using the prefix. (2a05:1111:222:3333::slight_smile:

If the router reboots or if I have the SFP interface or the PPPoE connection reconnected, everything works fine for about 30 minutes.
I can also ping services on the Internet via IPv6 from the router.
My WireGuard VPN can also successfully establish a connection and works.

After about 30 minutes, the router apparently can no longer use IPv6.
From that point on, it keeps trying to connect to the Internet using a ULA address (fd00:1337:420::).
This doesn't work because I haven't set up NAT for ULA.
As a result, the WireGuard VPN also stops working.
The router can no longer access the Internet via IPv6 until I re-establish the PPPoE connection and receive a new prefix.
I’ve also set up a client in DHCPv6 Client.
The prefix it receives is valid for 30 minutes. However, the countdown doesn’t have to run out completely for IPv6 to stop working.

grafik
grafik1515×874 226 KB

If I disable the client and re-enable it, IPv6 works again.
But that’s pretty annoying if I have to do this every 15 minutes.
The public IPv6 address is still assigned to the interface.
Restarting the PPPoE connection, the router, or the DHCPv6 client causes the router to receive a new prefix.

grafik
grafik1146×843 79 KB

All clients behind the router can still access the Internet via IPv6 without any problems.
There are no restrictions there at all. It’s just the router that’s not working anymore.

Everything was still working fine with ROS 7.24.5.
I didn't change anything in the configuration. Why would I?
It was working just fine.

I also happened to notice after the update that Neighbor Discovery was showing a message on all interfaces saying that the DNS configuration was incorrect and needed to be reset.
I simply applied the existing configuration again, and the message disappeared.
It didn’t come back even after I restarted the router.

Do I need to configure anything else now to make sure IPv6 works properly on the router again?

2

It's a bug introduced with 7.25. You can see in the 7.25 release thread 7.25 [stable] is released! that many including myself have encountered it. It only works until the DHCPv6 binding renews. That thread is read by MikroTik staff so maybe if you also add your experience with the bug there, MikroTik might give it a higher priority.

For now it's better to downgrade to 7.24.5 and wait for the big fix.

3

Oh man....
Thanks for the info!
I had found the thread, but not the mention of the bug.
Well, I'm glad I'm not the only one with this problem.

I guess I'll have to downgrade, too.

... The first bug in six years of using MikroTik that's really annoying.

4

You cann start with @eworm's post 7.25 [stable] is released! - #52 by eworm and the response chain that follows it.

5

For now, I've downgraded to 7.24.5.
Everything is still working there.

6

+1

I experience the same problem. I'm using IPv6-only Wireguard because of DS Lite. After upgrading to 7.25, after some amount of time the connection just dies. Servers in my DMZ are still available via IPv6 though. Just the router itself is not reachable any more.

I almost gave up while debugging; now I'm reading that it's a bug and affects other people, too. Thank you for bringing me relief.