Block dangerous LAN traffic

import-from-Redmine
2026-01-29T14:02:31Z

_Originally created by Tails on [#5293 (Redmine)](https://public-redmine-archive.tails.boum.org/code/issues/5293)_

It’s still not clear exactly what we want to do with LAN traffic in
general (XXX: this should really have a ticket), but ...

Originally created by Tails on #5293 (Redmine)

It’s still not clear exactly what we want to do with LAN traffic in general (XXX: this should really have a ticket), but on the short run, at least a minimal blacklist of known-bad traffic should be blocked:

It was reported that NAT-PMP can be used to discover the LAN’s external IP-address on the Internet.

Related issues

Related to #5340

Blocked by #7976 (closed)

Blocked by #15167