Select resolver automatically: tart ip --resolver=auto

[nirs]

tart ip requires the user to select the right resolver, which makes the command harder to use. It can be easier it tart ip will pick the right resolver for the user based on the way the vm was run.

• If the vm was run with --net-softnet: use dhcpd
• If the vm was run with --net-bridged: use arp

The new mode can be named "auto"

If we don't have info on the way the vm was started tart ip can check all resolvers before it fails.

[edigaryev]

If we don't have info on the way the vm was started tart ip can check all resolvers before it fails.

That's not an option, unfortunately, because it's inherently insecure: tart ip could pick up an ARP entry injected from the local network, and this network may be untrusted.

As for a more explicit option, this requires some way of communication between the tart run and tart ip.

[nirs]

If we don't have info on the way the vm was started tart ip can check all resolvers before it fails.

That's not an option, unfortunately, because it's inherently insecure: tart ip could pick up an ARP entry injected from the local network, and this network may be untrusted.

Good point, but this also means that using arp resolver is inherently insecure.

[edigaryev]

Good point, but this also means that using arp resolver is inherently insecure.

Not really: using an ARP resolver can be secure if the Tart user considers their local network as secure, including any other directly attached networks, such as VPN.

But the point here is that it's up to the user to explicitly communicate this, and this is why tart ip doesn't magically switch between these two methods of IP resolution.