Re: NM and IETF MIF working group

[Lubomir Rintel <lkundrak v3 sk>]

Hello Stjepan,

On Mon, 2015-09-07 at 12:05 +0200, Stjepan Groš wrote:
> Hi All!
>
> Two colleagues of mine and I started to work on MIF implementation on
> Fedora. In case someone doesn't know, IETF MIF working group
> (https://datatracker.ietf.org/wg/mif/charter/) tries to solve the
> problems of a single node having multiple parallel connections to
> different destinations (Internet, VPN, some private networks, etc.).

Thanks for the pointer, we'll definitely take a look.

> For
> example, probably it happened to you, as it did to me, that after
> connecting to VPN all my existing connections were terminated and also
> VPN allowed me to access only a restricted set of destinations meaning
> that I wasn't able to use Internet while the VPN was active. I hope that
> the work on MIF will solve this issue, as well as many others.

This was possibly because a default route changed to the gateway
obtained from the VPN gateway. It can be overriden with "ipv6.never
-default" and "ipv4.never-default" properties (can be set in nm
-connection-editor by clicking the "Routes" button and selecting "Use
this connection only for resources on this network").

> So, it seems to me that the NetworkManager is the core component on the
> client side that will have to have functionality specified by MIF
> allowing node to use multiple connections in parallel (this, of course,
> doesn't mean that it is the only component that will have to be
> changed). But since we are at the very beginning of this, we would like
> to hear thoughts from developers about this? Did anyone tried to do
> this? Give any thought to this and come out with a possible solution, or
> problems?

We do essentially deal with this to some extent by setting metrics to
the routes we set up. We assign priorities to different device types so
that e.g. Wired Ethernet is preferred over Wi-Fi or Mobile Broadband.
We do also remember order in which routes were added so that newly
activated connections on multi-homed hosts don't "steal" the existing
connections.

That said, I haven't really had a look (maybe someone else from the
team had?) at the documents you're created and discussed so far so my
understanding of the problem scope might be limited.

> Best regards,
> Stjepan Groš

Regards,
Lubo