On Sat, Jan 21, 2023 at 10:47:03AM +0100, Stefano
Brivio wrote:
Hi Noah,
Sorry for the delay, I didn't check pending mailing list posts for a
couple of days. Comments below:
On Tue, 17 Jan 2023 11:50:50 -0800
Noah Gold <nkgold(a)google.com> wrote:
> Hi folks,
>
> libslirp and Passt have different approaches to sharing DNS resolvers with
> the guest system, each with their own benefits & drawbacks. On the libslirp
> project, we're discussing [1] how to support DNS failover. Passt already has
> support for this, but there is a drawback to its solution which prevents us
> from taking a similar approach: the resolvers are read exactly once, so if the
> host changes networks at runtime, the guest will not receive the updated
> resolvers and thus its connectivity will break.
So, passt/pasta kinda-sorta binds itself to a particular host
interface, so DNS won't be the only issue if the host changes
network. For one thing, at least by default the guest gets the same
IP as the host, so if the host IP changes the guest will get out of
sync. We'll mostly cope with that ok, but there will be some edge
cases which will break (most obviously if after the network change the
guest wants to talk to something at the host's old address / its
current address).