The question, is why? Karlung urges subscribers of the affected ISPs to ask about their logging policies, and in particular, the motivation behind them.
“There is something not right here. Why do the other broadband operators save as much information about you as a customer, when they are not technically in need of it to deliver a contracted service? Ask them about it!”
Bahnhof itself says that it keeps IP-address logs for a maximum of 24 hours. They base this practice on a European Court of Justice ruling which concluded that the Swedish adoption of the data retention directive is invalid.
“To our knowledge, it’s Bahnhof and Tele2 who operate their IP logs in this manner, other Swedish ISPs are likely to follow the data retention directive and keep IP logs over the last six months,” Bahnhof Communicator Carolina Lindahl tells TF.
I have never understood most log retention policies. I try to keep as little as possible, and it works out fine.