Almost one million Deutsche Telekom customers have been struggling to get online since Sunday afternoon.
There's nothing wrong with the network, the company said, advising customers having trouble connecting to the internet to turn their router off and on again in the hope of solving the problem.
Around 900,000 lines were initially hit by the connection problem, although the number affected is falling, Deutsche Telekom said Monday. But that number may be an underestimate: Since some of the affected routers also provide subscribers with telephone service, customers may have no way of letting the company know they are having difficulties.
The cause of the outage is unknown, with those affected living in different areas and using different routers models, the comapany said. It dismissed suggestions that the problem was worse in congested areas.
One possibility raised by the company is that the affected routers have been targeted by an "external influence," which is preventing them from logging on to the carrier's network. Deutsche Telekom didn’t respond to a request for further information.
Deutsche Telekom sells a handful of modem-routers under the Speedport brand, but in Germany subscribers are free to use modems from any vendor that meet network interface standards.
German manufacturer AVM said Monday that its Fritz!Box products were not among those affected by Sunday's problem.
It should come as no surprise when routers are blamed for succumbing to nebulous external influences: Even products from reputable manufacturers ship with software flaws that leave them vulnerable to hackers. This year alone, security researchers have found holes in products from Ubiquiti, Netgear and D-Link, and a whole slew of devices using insecure Telnet connections for remote administration. Other attacks have targeted as many as 40 router brands.
If it does turn out that the outage was caused by hackers, then there are a number of things router users can do to protect themselves in future, in particular changing default settings.
Meanwhile Deutsche Telekom is offering subscribers affected by Sunday's outage unlimited free mobile internet access while the problem persists. T-Mobile users can get the freebie online at http://pass.telekom.de, while customers of other networks must head to their nearest Telekom shop.