IPv6 tests success initially, failing after some time

kosymodo

kosymodo

kosymodo

Associate
Joined
18 Jun 2020
Posts
382
Location
Warminster
Right then folks, here's a bit of a weird one...

I've recently had a tinker with my network, and along with a change in FTTP provider, have now got Pi-hole and Unbound set up as my DNS server. This is also after having updated my various RPis from 3B/4 models to all 5 models.

Don't ask me why, but I like to run the IPv6 tests to check that I have decent scores. I know IPv6 is not really all that necessary (though, of course, it's getting more and more necessary), but let's say I like to be ahead of the game ;)

What I'm finding is that if I run the test soon after my laptop is booted, I get a perfect 10/10 score. However, if I run the test later on, I get a 0/10 score, as a result of no IPv6 address detected. This is the same on both my work and personal laptops. I'm scratching my head as to why an IPv6 address is detected initially, but not later on.

Any ideas?
 
Which ISP? Do the laptops show an IPv6 address if you check in powershell/command prompt? What happens if you do 'ping -6 google.com'? What happens if you do 'ping -6 2001:4860:4860::8888'?
 
Hmmm OK, further to my post #4...

Those tests were immediately after coming home from being in the office today. Upon retesting 10 mins later, both the pings time out :(
 
Hmmm...so this is getting all the more strange

Personal laptop still fine

Work laptop not fine. Was pinging -6 google.com OK, then stopped working. All I did in the interim was to ssh into my Pi.

Just tried the same on my personal laptop (i.e. ssh'ing into my Pi and out, then trying the ping again) and still working.
 
the-evaluator said:
All good there. Did you do those tests whilst the checker was reporting thumbs up or thumbs down?

Which IPv6 checker are you using?
Click to expand...
Those were immediately after logging in, so would have been while the checker was reporting 10/10. When it reports 0/10, pings time out.

I'm using ams2.test-ipv6.com because using test-ipv6.com fails whatever device I'm using (something Pi-hole/Unbound related I believe, I've reached out to the Pi-hole discourse community to get this resolved)

As of this morning, I'm using Pi-hole as my DNS server, and my personal laptop is working perfectly. However, my work laptop initially reported 10/10, but stopped working shortly after logging in (0/10 and pings time out)
 
You don't mention your router or IP setup (are you delegated a /56 or /64, using DHCPv6, or something else?). When it happens, SSH into the router and check the IP assignments (ifconfig or ip a) and see that it still holds the /56 or /64 or whatever you have delegated. Restart the PPPoE session if applicable and test again.
 
Rainmaker said:
You don't mention your router
Click to expand...
UDM Pro

Rainmaker said:
or IP setup (are you delegated a /56 or /64, using DHCPv6, or something else?).
Click to expand...
DHCP range is /64 using DHCPv6

WAN is /62 using DHCPv6

Rainmaker said:
When it happens, SSH into the router and check the IP assignments (ifconfig or ip a) and see that it still holds the /56 or /64 or whatever you have delegated. Restart the PPPoE session if applicable and test again.
Click to expand...
I'm on a static IP using DHCPv4, so no PPPoE session to restart
 
Last edited:
@Rainmaker only today getting round to checking this as I haven't needed to use my work laptop over the long weekend.

Ping -6 google.com gives an error of 'Ping request could not find host google.com. Please check the name and try again.'
Ping ping -6 2001:4860:4860::8888 gives an error of 'PING: transmit failed. General failure.'

When you mention to SSH into the UDM Pro to check the IP assignments, won't this just be the same result as checking the GUI?
 
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