control: tags -1 -help +confirmed I reproduced the problem with a podman container with no network. Apparently t_iprop.py hangs if the only network interface is loopback. I'm fairly sure it would work fine only talking to itself if there was a non-127.0.0.1 address for it to use.
If I can fix this easily, I'll do so. Otherwise I'll engage with the sbuild maintainers. It's always been the case that builds have had a network interface, even if it has been illegal to reach off the local machine. Kerberos has always treated lo different than other local interfaces; the rationale for this goes back to the Kerberos standard (RFC 4120). --Sam