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VMWare Fusion and network bridging

** UPDATED MARCH 12 2010:  I just posted my solution to this problem here **

I’ve had VMWare Fusion running an image of my work laptop, on my Macbook, for nearly three weeks now. I’ve had no problems at all, running over both NAT and via network bridge.

Until this week.

Now, when I try to use the image over network bridge I get the error “The network bridge on device /dev/vmnet0 is not running”. It still works over NAT but i’m perplexed as to where this problem has come from. No software updates, no network config changes, nothing that I can think would affect this at all.

I started to wonder if it was something to do with being assigned a bridged DHCP on my home lan (10.0.0.X), suspending and being brought up on the work lan under a different subnet completely. Maybe something was going majorly wrong with the bridge device.

I couldn’t/can’t find anything logged anywhere other than the error message above in the vmware.log within the VM image folder.

Running the following command restarts all the vmnet related services:

/Library/Application\ Support/VMWare\ Fusion/boot.sh –restart

You’ll need to sudo that command.

I haven’t found anything on the VMWare community forums to indicate that this has been bugged for fix in a later release so i’m still not entirely sure of the cause…


  1. Ammoun says:

    Macca, I also ran Fusion 2 for 18 months without ever encountering the NAT/Bridged connection errors. However, I was running Win XP not Vista nor Win 7. With Win 7 and Fusion 2 I could connect only in NAT network type not Bridged, no matter what I did.
    Now in Fusion 3 and Win 7 it is even worse, it is erratic and I cannot figure out what is happening! I only know it is a DHCP problem because when I use a VPN or set my own IP and specify the Gateway and DNS servers, I connect to the Internet with no problems as the VPN assigns me an IP and somehow things work fine.
    As I am no expert in networking, Win 7 or Fusion I can only state my observations and hope they are of use to some guru out there who may come up with an answer for those of us suffering from this incompatibility or whatever you may call it.
    I only wish I was as lucky as you with this issue.

  2. ammoun says:

    Just to confirm, if I set my own IP address, Gateway IP and DNS IP, my “Bridged” network adapter works fine and I can see my network printer …etc. If I leave the IP to Automatic then I cannot see the printer, my “Bridged” network adapter setting does not connect to the internet, my “NAT” connects, however it fails to see local network, only the internet! This is weird and most definitely has to do with the VMware/Win 7 combo failing to obtain and IP address (register on the network) properly. Any suggestions from anyone? I do not wish to keep my IP set as I move from one WiFi network to another at different venues.

  3. ammoun says:

    I just tried a fresh Win 7 installation with Parallels Desktop 5 and it is exactly the same problem as with VMware Fusion 3 with Win 7. So…. it seems that the problem is Win 7 (and Vista before it)! This is as far as my knowledge goes! Anyone with an answer?
    Bless you all.

  4. ammoun says:

    I changed my router to Belkin N1 (from LiveBox that came with my ISP provider’s subscription) and my NAT and BRIDGED networks both worked well!! It seems that neither VMware Fusion v3 nor Windows 7 are at fault, it was my router!! So please try to change your routers or fiddle with the settings!
    Bless you all.

  5. ammoun says:

    I am sorry, I rushed my comment! I restarted and found out my NAT network does not “see” my printer or other computers on my local network! We are back to square one with no help from VMware or Microsoft!

  6. ammoun says:

    My final comment and the resolution of my problem; as explained to me by the VMware support (very good people indeed); NAT networks use virtual IP addresses assigned by the virtual machine’s DHCP not by the router and hence the virtual machine is not given an IP in the physical local network which explains why NAT networks do not “see” network printers and other computers on the physical network (router and devices connected to it), it only connects to the internet through the NAT (and router) and connects to the MAC of course.
    Bridged networks, however, obtain an address from the DHCP of the router and are, therefore, part of the physical network and hence can “see” the local network devices and other computers connected to the router and are on the network along with the MAC of course.
    The above has been the case since I changed my router and so I am now OK. Support tells me that some routers act weird and for some reason refuse to assign IPs to some computers on the network and this is documented with several models out there. So, if your computer is not able to get an IP from the router or the router is failing to act as a DNS for your network in Bridged network configuration, then try another router before anything else.
    I hope this is useful to someone.
    Good luck to all and God bless.

  7. […] couple of years back, I posted this thread about an annoying problem in VMWare Fusion which occasionally stopped me from being able to run an image as in bridge […]

  8. Peng Lie says:

    Today I upgraded the iMac of my wife to Snow Leopard. Fusion 2 with XP in bridged mode is still working normal. Later I upgraded Fusion to Fusion 3.0.2 and bridged mode with autodetect is not working. If you restart XP it received an IP address and the Network Connection looks ok until you use the network. If you repair the connection no IP address is received from the DHCP server. If you choose for Ethernet or Airport instead of Autodetect the bridged network is working fine.

    My conclusion is that the problem, at least at this iMac, is introduced by Fusion 3.0.2.

  9. Ash says:

    It worked for me! Thanks~!

  10. A. says:

    Worked for me as well. Many thanks; I only wasted $800 worth of time trying to overcome this stupid bug…

  11. QS says:

    I had the exact same issue, running fine for ~18 months, then suddenly this issue. Running the network restart command resolved it straight away. Much appreciated, thanks!

  12. Orwellophile says:

    It happens to me when-ever I reboot my hub. I guess it would also happen if your network link were interrupted for any reason (pulled cable, etc). I’ve always assumed it had something to do with the vmware network drivers.

  13. sockmonkeysteve says:

    I know this is an old thread; sorry to resurrect it.

    But I’m having this issue suddenly start occurring under Fusion 5 [Version 5.0.3 (1040386)]. And only on certain VMs, too. Very, very frustrating. Unfortunately, bridging to a specific network (vs. autodetect) no longer is a quick fix (at least in my experience thus far) and I have also been unable to locate a boot.sh script to run either.


  14. Ian says:

    I’ve actually moved to Parallels this year (I switch between the two pretty regularly) so I don’t have a copy install to refer to.
    I think the newer versions of Fusion actually expose a lot more of the networking aspects now so it’s a little more comparable to the Windows version.
    You could try switching your network settings there to see if it’ll reset the adaptor settings…

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