[blablablaat]

This is probably NOT a backdoor.

Most likely your ISP is using a technique like TR-069. This enables them to push settings for voip/TV, and in your friends case wifi. A lot of DSL providers are starting to use this for less intrusive (?) goals like measuring noise and attenuation at the clients end once a day, so they can adjust the speed accordingly.

AVM is a very nice company and you should not accuse them without proof. They actually provide an option to disable TR-069 in the page "Provider Services" ("Allow automatic configuration by the service provider" and "Allow automatic updates"). If you don't have this option you could try installing the original firmware from avm.de. Maybe you are still able to flash the modem with the original firmware from , and configure it yourself?

[bjornsing]

> AVM is a very nice company and you should not accuse them without proof.

You shouldn't accuse anybody without proof. But since this is Hacker News I'll disagree with the first part of that sentence. AVM is probably the least hacker-friendly company I've ever come across. For example, they're so hell-bent on violating the GPL that they've taken it to court (and lost) [1].

1. http://fsfe.org/activities/ftf/avm-gpl-violation.en.html

[pktgen]

> A lot of DSL providers are starting to use this for less intrusive (?) goals like measuring noise and attenuation at the clients end once a day, so they can adjust the speed accordingly.

Why can't this be done on the DSLAM?