Wojtek Bednarzak

(Temporarly) Living in a IPv6 only world

11 Dec 2019

On the evening of 2nd December, I have noticed something funny - only half of the internet was working. The other half? Disappeared off the planet.

Google - works, Github - gone. My website - empty as always, but here, Slack - nope. Work VPN - unsuccessful DNS. So thinks were bad, but not horrible.

So what was happening? Quick ip addr showed me one thing - no IPv4 addresses were assigned locally, checked on whatsmyip.com and I was greeted with Your IPv4 is: Not Detected. Our ISP is Virgin Media, and they provide dual stack to homes now - IPv6 being primary, with IPv4 for fallback. I am quite happy about it. Loads of cheap VPS providers will give you IPv6 for free, with IPv4 being available for an extra fee. But you still have that IPv4 just in case someone refuses to move to the newer standard.

So how is the experience? Good and bad. Wide range of sites down work, but at least you can see who cares about being a good internet citizen and supporting latest standards. People at the time of the incident complained about Virgin Media breaking the internet for them, and while this is correct, it is also up to websites to add IPv6 functionality, because in most cases its not hard, just slap a CDN like Cloudflare and you are done. The ironic thing is that the Virgin Media site itself is IPv4 only, making their status page useless.

In the end it turns out it was a bad device on the network. I am not a networking expert, but it looks like a new switch was reporting that a device connected to the switch was assigned all IP addresses. Unplugging and plugging it back in solved the problem. I was suprised however that a single device would kill IPv4 connectivity, and somehow it was not translated back to IPv4 by the router. I might however just show that I have massive gaps in how this whole thing works and I need to read up on it more.

My conclusion: Highly recommended (that everybody should switch to IPv6)