[apk17]

Partially. Telekom keeps up the line for months at a time. I guess that is due to telephony being done via VoIP, and they don't want to interrupt your late night calls.

Others, even Congstar (which is a cheap telekom brand), do 24h disconnects with a new v4 address, and no v6 at all.

The DSL I use gives me a fixed v4 and v6 range, but still needs to do the daily disconnects.