GNS3 & VMware

Well I’ve been back using GNS3 to simulate some networks professionally.  And well, I hit a roadblock of a strange kind.

In my “LAB” I want to have a ESXi host talking to vCenter, and I wanted to setup a custom logging program which logs to MSSQL, and Maybe Oracle.  For routing I need Junos and cisco IOS.

Now the problem is that takes a little bit of everything.  The Qemu bundled with GNS3 horribly ancient, and my attempt to drop in Qemu 1.6.0 just fails.  Also running things like Windows Server 2008r2 and ESXi run best under VMware.  The SQL server stuff can be any version, so even NT 4.0/SQL 7 is fine which GNS3’s Qemu can run, but it is kind of slow.  Which I know it isn’t fair to compare something like Virtual Box to VMWare.

So ideally the best  bet is to tie them all together, and I found a way.

First I’m using VMWare Player version 6.0.1 build-1379776.  The people financing this insane project have things like VMWare workstation but I have to download it through them, and their link is insanely slow, so I’m sticking with the player for now.  But I was able to persuade a user to extract “VMware Workstation 10.0.2 build 1744117”, and retrieve two files for me,  vmnetcfg.exe and vmnetcfglib.dll.  So this way I can setup VMWare network interfaces which GNS3 can then latch onto with pcap.

The feature was available in earlier versions of VMWare Player, but the needed files were removed in the latest version.  However I found if you have access to a new version of VMware Workstation you can just snag these two files, and run them like this (as administrator):

rundll32.exe vmnetcfglib.dll VMNetUI_ShowStandalone

And now you can setup some networks.


VMware’s default network setup

Now from what I have read online, the best thing to do is leave the default networks alone.  However I found that if I left VMNet0 to the defaults I was unable to join any VM’s to the different networks.  So I bind this to my physical Ethernet connection.

Now I want to have various network points to attach VMs onto.  The best part that I’ve found is that pcap works on these networks for both listening and injection, so these make better ‘hub’ inspection points IMHO.  Also this means you can run emulators that inject libpcap as a method of communication (SIMH, WinUAE, and even my ancient Qemu 0.9.0…)

The big thing is when adding networks, DISABLE DHCP.  You can leave the rest where it is, it really doesn’t matter.

With Networks

With Networks

As you can see, I’ve now added VMnet2 – VMnet7.  This should give me enough user networks for now to play with.  I’ve also unchecked the local DHCP service, as I may want to run my own DHCP on an emulated server to make sure DHCP relay works through my virtual network.  Once you are happy, you can hit Apply and it will create the network interfaces on your computer.

So many networks!

So many networks!

Now going into the control panel, and looking at the network adapters (search for “view network connections”), and you will see there are a bunch of these VMWare Network Adapters.  The worst part is that they all have full networking enabled, which we don’t want. So starting with VMnet2, we need to unbind all high level access.



I unbind the ‘Client for Microsoft Networks’, ‘File and Printer Sharing for Microsoft Networks’, and TCP/IP version 4 and version 6. This the Link-Layer topology discovery stuff.  I also enabled the VMware Bridge Protocol.



Now I just have to repeat this for each of the adapters that we installed, in this case VMNet2 – VMNet7.  Remember to leave VMNet0, VMNet1 and VMNet8 alone!

Now for the real fun, you have to reboot for the changes to take effect.

After a reboot, if you run Wireshark, you should now see all the interfaces!

Wireshark  with the new interfaces

Wireshark with the new interfaces

Ok so far, so good, but let’s tie this mess together!

HHGTTG refrence

HHGTTG refrence

So let’s build a network.  Our “home” site will have a server network with the ESXi server serving some virtual servers, a user network which will contain our management workstation & a MS-DOS netware machine.  We will then have a remote network with different machine types, which will be a 4.3BSD VAX, and an Amiga running NetBSD.  We’ll also include a Novell Netware 3.12 server.  Add in an ‘internet’ router, and we should be good.



The first step is to create some clouds.  Each one of these will then be associated with a VMNetwork device.

Network Device
Server VMNet2
Vax-Amiga VMNet3
NetwareServer VMNet4
Client VMNet5
Internet VMNet8

Now you’ll notice that I’m assigning VMNet8 to the ‘internet’.  If you remember the original VMWare table, the VMNet8 device is a ‘NAT’ device.  So we can use that to get to the internet (well anything else the base device can access).  Now I’ve gone ahead and added in two cisco routers, a single juniper router and a hub, as the juniper device cannot directly connect to the Internet cloud, but using the hub for the intermediary is ok.

Add in the routers & hub

Add in the routers & hub

Now it’s time to add some interfaces to the routers.  I’m going to put the C7200-IO-2FE into both R1 & R2, along with a PA-4T+ serial adapter.  Because I want to pretend to have a fast internet connection I’m also going to place a PA-GE interface into R1 in slot 2.

Now we need to bind each cloud to the corresponding VMnet interface.

Server Network

Server Network

Simply double click on the cloud, and select the VMNet interface from the drop-down list, then add it and the interface is now bound.  Repeat for each of the clouds.

Now we can connect the interfaces.


Now with Interfaces

Now with Interfaces

So R1’s FA0/0 is connected to the SERVER cloud, FA0/1 is connected to the CLIENT cloud. Serial 1/0 is connected to R2’s Serial 1/0 interface. the G2/0 interface is connected to Junos1’s e1 interface

R2’s FA0/0 is connected to the VAX-AMIGA cloud, and the FA0/1 is connected to the NETWARESERVER cloud.

Junos1’s e0 is connected to HUB1, which is then connected to the INTERNET cloud.

NAME Interface IPX IP
Server VMNet2
Vax-Amiga VMNet3
NetwareServer VMNet4 cab2
Client VMNet5 cab3
Internet VMNet8 DHCP
serial none cab0
GigE none
Configure the network interface in VMWare Player

Configure the network interface in VMWare Player

Since I already have an ESXi VM on Player, I’m going to use this for my illustration.  All I need to do here is change the existing network from being ‘bridged’ on my native network, to now being on VMnet2, which now places it inside of my GNS3 world.  Likewise I take a Windows XP client, and place it on VMnet3.

Now to configure R1 like the following:

Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 YES manual up up
FastEthernet0/1 YES manual up up
Serial1/0 YES manual up up
GigabitEthernet2/0 YES manual up up

And R2 like the following:

Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 YES manual up up
FastEthernet0/1 unassigned YES unset up up
Serial1/0 YES manual up up

And now I can connect from my Client PC, the VMware ESXi server!



This gives me an easy way to ‘view’ into what is going on for my client to connect to the server.

Now some quick EIGRP to get R1 & R2 routing together..


router eigrp 1
no auto-summary


router eigrp 1
no auto-summary

And now we can check routs on R2, and see it’s learnt the routes from R1: is subnetted, 1 subnets
C is directly connected, Serial1/0
D [90/2172416] via, 00:15:50, Serial1/0
C is directly connected, FastEthernet0/0
D [90/2172416] via, 00:15:50, Serial1/0

I was a little disappointed though, that Olive can’t do any flow based stuff like security policies or NAT.

So onward with SIMH.  I’ve found that I have a LOT of Ethernet interfaces and some things cannot deal with that.  I had to make a trivial change to sim_ether.h:

#define ETH_MAX_DEVICE        32                        /* maximum ethernet devices */

SIMH had this value hard-coded to 10, and it crashed because I have… 11 interfaces.  So it just took a quick re-compile and now I can see my interfaces!

0 \Device\NPF_{0C6D7EF7-30D4-4AB0-AB3E-AC6EAB42B9C5} (VMware Network AdapterVMnet2)
1 \Device\NPF_{1A17F8DF-DC65-420E-9A7A-3F8D22EC0D12} (VMware Network AdapterVMnet6)
2 \Device\NPF_{5A889C62-8180-4DB5-8FFE-3B6B8B9DFFAF} (VMware Network AdapterVMnet7)
3 \Device\NPF_{A6B89C5C-C28C-424E-B795-F90F97FA0FE7} (VMware Network AdapterVMnet8)
4 \Device\NPF_{21FFD0D4-1B8B-47B7-B0DD-28CD67DF4080} (Local Area Connection)
5 \Device\NPF_{70AA2D26-7B96-42FB-9FA6-8A7386753099} (Local Area Connection 2)
6 \Device\NPF_{98F44EE6-626B-48CB-952D-9C890F44A4A5} (VMware Network AdapterVMnet5)
7 \Device\NPF_{D294A70E-07B3-4CA8-A88D-D6C392696E99} (VMware Network AdapterVMnet1)
8 \Device\NPF_{F746872D-7687-4867-958C-96A62BA5E284} (VMware Network AdapterVMnet3)
9 \Device\NPF_{783262C6-8B95-4F9E-B198-78E2D9B256BB} (Bluetooth Network Connection)
10 \Device\NPF_{D6726593-C290-4821-8D43-D180CF5631BA} (VMware Network AdapterVMnet4)


So with SIMH I can now attach to eth8, which maps to VMnet3.

set xu ena
att xu eth8


Easy, right?

And even better, it works!


Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/15/28 ms

And the XP workstation can telnet to it…

VMWare routed through GNS3

VMWare routed through GNS3

Next I’ll have to add in some NetWare fun.  For the heck of it.  Good news is that it works!

One caveat I’ve found is that sometimes the ARP response time isn’t so hot, and it seems like everything times out..  So you may want to tweek the default arp age on the cisco side (interface bla/arp timeout 600..?).

This entry was posted in cisco, cisco networking, virtual networking, VMWare by neozeed. Bookmark the permalink.

About neozeed

What is there to tell? I've loved UNIX like things since I was first exposed to QNX in highschool (we had the Unisys ICONS!), and spent the better time of my teenage years trying to get my own UNIX... I should have bought Coherent in retrospect.. Anyways latched onto Linux in 1992, and then got some old BSD admin books and have been hooked on the VAX BSD & other big/ancient things since...!

11 thoughts on “GNS3 & VMware

  1. Impressive! That’s something I always wanted to do as well.

    I recently found out about Linux network namespaces. With that as lightweight virtualization, you can easily run more/different emulators (TME, Data OnTap 7, HP Simware …) which are only available for Linux, without the need to create a VM for each. You can also simulate very simple routers via Quagga, which requires far less memory than a “full” Cisco router.

    I started writing a small wrapper script which can set up various simulators/routers/hypervisors and connect them together from the commandline, something like MiniNet, but without the “SDN” stuff


    • I’ll have to look at that… Although I know I’m weird in that I don’t want lightweight networking, I want heavy stuff as I need to make sure that I can connect to various IOS and JunOS devices, and look for certain things in the network as I remove links, shut stuff down, have machines communicating or not communicating.

      But for “normal user” yeah it’d make more sense for sure!

      • You can still do that and run concurrent dynamips processes in the various namespaces without any problem. The nice thing is that you can use the standard UNIX network tools and even run regular binaries in the namespaces without the need for virtual machines. “ip netns exec ns1 /usr/bin/firefox” for example is much faster than building/starting a VM…
        And of course you can still run wireshark on the “virtual” ethernet links. There’s even an mstpd daemon that’s supposed to enhance the regular Linux bridges with the MSTP protocol (something you cannot currently do with dynamips) but I couldn’t get it working correctly yet…

    • because I bought this, it was on sale.. Once I noticed its QOS software holds you to your internet speed (and then disabled it), it’s not a bad board.

  2. Hi,

    If you convert this config to MAC, does this mean you will create vmnets on the virtual machine > vmware fusion > preferences > + add network adapter…

    and from there you will use bridge mode and not custom network?

    • I haven’t tried this on VMWare Fusion, but the key here is that you need to add ‘virtual’ network interfaces that the OS can interact with. On Windows you can also add “Microsoft Loopback Adapters” to build virtual interfaces.

      But basically the OS only provides the medium for VM’s to plug into, and GNS3 does any/all routing/bridging between virtual interfaces.

      • what do you think is the best vmware for windows to use for GNS3? Is it the free vmware player? (I have the vmnet config all ready to for this!) or the vmware workstation that is free only for 30 days and just call vmware to reset it?

      • I use VMWare Player (aka the free one). Once I got the utility to configure the vmware networks, and set them up to bridge into GNS3, it’s basically all I need. I’m emulating servers, and basic workstations so that’s all I need. Also the free Player can run ESXi, if you really want to go crazy. But you’ll want LOTS of memory!

    • I remember it was slower than I liked, but I think that was more so due to the complexity of emulating netware… the whole thing was more of an exercise in wow factor.

      As always, I recall it handling NT 4 TCP MUCH better….

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