Monday, March 25, 2013

GNS3 - Connections to the Real World through ESX

Gday again.

Well now that I'm back in Cisco land at work I thought I'd take full advantage of being able to lab things up in GNS3 now that I've exceeded the capabilities of Packet Tracer...

I remember running up GNS in the past and remembered having a horrible time getting things to work.

Well good news everyone!

It works like it's supposed to now!

It's seriously easy to install on a Windows box.

Just follow the quick start guide and you'll be up and going in no time :)

After you've got some virtual routers up and running don't forget to set your idlepc values otherwise your physical or VM guest CPU will get chewed up very quickly.

Now that's all well and good, but how do you connect a virtual router to your real network I hear you say?

Well it's not hard at all (although you'll get a bit of a bum-steer following guides floating around the net...).

There's a guide available over at the GNS3 site however I found I had to do things slightly differently to get things working...

The first step is to add a cloud to your topology and add the Local Ethernet Adapter as an interface.

Next add a router, power it on and configure an interface with an IP address in the same subnet as the adapter to which the VM guest NIC is assigned.

It's important you do the cloud first before the router otherwise the connection won't work (all you need to do is restart your router if you did it the wrong way around).

Add a link between the cloud and your router (hint: the connection tool will always choose eth 0/0 on the router first) and you're done for the GNS3 part.

Now back in your vSphere client go to the host configuration tab and click Networking.

Select the network you've setup from the Network Ports list and enable the tickbox for the option Promiscuous Mode.

Finally, get some ping action happening and see if your virtual router is now reachable from the real world (and vice-versa).

Enjoy :)

1 comment:

  1. Hello,

    i followed the steps but i can still not ping GNS3 Router to other devices