Comment # 1 on bug 890942 from Marius Tomaschewski

(In reply to Ralf Friedl from comment #0)
> Actually in this case it is not even necessary to reconfigure the network

ack.
I think yast2 is simply unable to detect what it effectively changed.

> But anyway, it should be possible to call "rcnetwork restart" without
> causing that terminal to hang. 

It is "magic" why systemd sometimes results in a systemd-tty-ask wanting
something. The network scripts themself never request any passwords which
would cause to ask user for something.

A "systemd-tty-ask-password-agent --list" could perhaps show what really
needs a password from systemd.

It could be something "foreign" started via if-up.d hook scripts or even
more probably some service doing it gets restarted because of dependencies.
The --ignore-dependencies and/or --no-ask-password options could help here
[can be also passed to network script via SYSTEMCTL_OPTIONS variable]...

Similar to DHCLIENT_MODIFY_SMB_CONF=yes in network/dhcp as a known source
to cause dependency loops (systemd blocks an action to a service because an
another in dependency chain is currently running an action) -- the if-up.d
script handling it is installed by samba-client...

> It seems the second attempt at rcnetwork restart managed to unconfigure
> the network, not I don't even get responses to pings and therefor can't
> open another ssh connection to the server.

This is probably the garbage collector in systemd: kills services when they
do not response for a while -- here, caused by the systemd-tty-ask.