[Netkit.users] netkit and dynamips/dynagen/gns3

Massimo Rimondini rimondin at dia.uniroma3.it
Thu Sep 4 15:59:03 CEST 2008

Dear Cedric,

Cedric Foll wrote:
> Hi,
> i'm trying to use netkit machines with cisco routers emulated with
> dynamips/dynagen/gns3 (cf http://www.gns3.net/).
> The only way i found is using clouds on gns3 (it connect a router with
> a tap interface, let's say tap0), then I connect a netkit machine with
> an other tap (nk_tap_cedric).
> Finaly i bridge tap0, nk_tap_cedric and remove iptables rules added by netkit.
> I have a netkit machine connected to a virtual cisco router by bridge
> br0 on my host:
> R0 <->tap0<->br0<->nk_tap_cedric
> If i want to connect an other netkit to an other router or interface
> of my router i have to create an other use account on my host (let's
> cedric2) and run netkit on this user account will create a new tap
> interface nk_tap_cedric2. Finaly i bridge tap1 and nk_tap_cedric2 and
> so on.
> So it works and permit to create very interesting labs but that's not easy.
> Is it possible to modify netkit in order to choose a new tap interface
> for each UML machine in next release?

That would not be straightforward. I agree with you that the currently
available mechanism to configure tap interfaces is not flexible enough
to support these scenarios (and some others). Therefore, we will likely
reconsider it in next releases.

> Even better, Dynamips/dynagen may be directly integrated into netkit?

Again, the question is about flexibility. Making virtual network
connections more configurable requires some not-just-superficial changes
to Netkit. Accommodating other emulators requires even more. Both
challenges are definitely worth the effort, and we have been long
thinking about them, but I can't tell you if or when they will make to a
future release.

> Regards.
> _______________________________________________
> Netkit.users mailing list
> Netkit.users a list.dia.uniroma3.it
> http://list.dia.uniroma3.it/mailman/listinfo/netkit.users

However, I find your approach of combining Dynamips with Netkit very
I'm not sure, but the implementation of your scenario could probably be
slightly simplified by directly fiddling with the manage_tuntap script
used by Netkit to set up tap interfaces (at least, you wouldn't have to
use a separate account). If you are interested I can verify this and, in
case of success, provide you with the details.


More information about the Netkit.users mailing list