An Update on Unitymedia – The Odyssey Continues

Never got around to publish this. This article is about half a year old by now. But as the old saying goes: Better late than never.

In a [not so] recent post, I wrote about my Internet Service Provider (ISP) Unitymedia and the problems I had with them. In the weeks after I wrote my blogpost, everything seemed fine. Until two weeks ago, when Münster (and the rest of Germany) was hit by quite a few thunderstorms. During one of them my modem (Technicolor TC7200) rebooted. At first I did not notice a change, but a few days later, I tried to connect to my home network from work, and realized it didn't work.

The Return of IPv6

When I returned home, I restarted my Raspberry Pi thinking it had crashed. Still no incoming connectivity from outside my home network. I rebooted my router to be sure it didn't crash. I checked my router's config, because sometimes the TC7200 gives it a wrong IP address, not this time. Then I went to check on the DMZ (De-Militarized Zone) configuration of my modem and it hit me. The DMZ configuration menu was gone, I checked on the IP information screen and saw my modem acquired an IPv6 address and switched back to IPv6 mode – the one utilizing my provider's CGN (Carrier Grade NAT, see my older post). Fed up about my ISP’s incompetence I sent them an e-mail describing my problem.

The next day I got an e-mail from Unitymedia telling me they tried to call me (at home, in the middle of the day). Back home I dialed the telephone number I was told to call in the e-mail and sure thing I reached the main support hotline. I was told that all their systems showed my modem still received an IPv4 address, but my modem disagreed. They told me to disconnect my modem from power for a few minutes to reset it and then reconnect it. Guess what, it didn’t work. Also since my landline telephone connects through my modem, restarting my modem means hanging up on the support hotline. Before hanging up, their support agent told me he was forwarding my ticket to the tech department. Then nothing happened... for about a week.

The issue gets annoying

Not only that my devices were not available from the internet, but also certain services weren’t usable from inside my network. The most annoying thing was Netflix. Somehow, and I don’t know who is to blame, Netflix is only available via the IPv4 Unitymedia network, IPv6 won’t load at all – at least the apps. Netflix seems to have major problems with IPv6 in general and their recommendation is basically “switch off IPv6” to which my answer usually would be “switch off Netflix”.

After that week I called the support hotline again, asking what happened with my ticket, they told me they sent a text message to my mobile, but I didn’t receive anything… So they told me to disconnect and reconnect my modem again, that didn’t work either.
The next evening I called them yet again, and was told I needed to disconnect and reconnect my modem once more for ten minutes, because otherwise their support software wouldn’t let them initiate the next step – great customer experience :-/
I did that, didn’t help. So I called them yet again – each time having to describe my issue from scratch – when I finally got a competent support agent who understood my problem, documented it properly and also wrote down that this connection was also used for business purposes. The next day I got a text message apologizing for taking so long to resolve the issue and telling me it might take a bit longer. Next morning I got another text message telling me the issue would be resolved shortly. Ten minutes later my connection died because my modem suddenly rebooted – great if your provider suddenly has more control about a device on your network than you do, isn’t it?

After the reboot my modem suddenly had proper IPv4 connectivity again – yet it is still unclear to me what caused the problem.