On 26 Jan 2018, at 05:18, Andreas Krey <a.krey@gmx.de> wrote:

On Thu, 25 Jan 2018 19:06:40 +0000, Peter Ott wrote:
...
release upgrade-. A change of the IP-adress seems to be handled fine by TOR.

That is only true for the client side.

Tor relays autodetect changes in their IPv4 address, and publish a new
descriptor containing the new address.

This change by the ISP occurs at least every 3 days or so).

Clients address guards by their IP address, and they try hard
to only talk to their selected guard. If that guards hops to
another address, they have no chance of noticing that and
need to select another one.

When the client gets the new descriptor (1-4 hours after each change),
it will use the new IP address. Until then, the client would use its other
primary guard.

That makes your node pretty useless as a guard, and it shouldn't
be elevated to guard status.

The directory authorities regularly check the reachability of each relay.
When your relay changes IPv4 address, some authorities might find it
unreachable before it finds out itself, and publishes a new descriptor.

This is probably why your relay does not have the stable and guard flags.

But your relay is still useful as a middle node. And it frees up guard
bandwidth to be used for direct client connections. This is particularly
useful right now, because guards are under extra load from some
clients that were added in December.

T