I'm using VMWare Server (currently on Version 1.0.7) and have two VMs that I would like to run at the same time. However, I'm having problems in setting them up so they can ping each other.

I've configured them to use 'Bridged' networking. They both obtain an IP address from the DHCP server on my network, but after that they can't ping each other. It seems that only the first one has a functioning network connection (I can ping it from the host machine and Internet connection works), but the other one does not. If it helps, both VMs are running XP SP 3.

Any ideas? Thanks!

2 Answers 2


Sounds like you've done everything right to accomplish what you're looking for.

Did you "clone" or copy the VMX file for one VM to create the second? It's theoretically possible that they're using the same MAC address, which will lead to all kinds of craziness.

Is the problem any different when only the "problem" VM is powered on?

Since the "problem" VM is pulling an IP address from DHCP I tend to think its able to communicate over its virtual NIC and that, at this point, you've just got a network communication troubleshooting problem not unlike what you'd have with a physical machine having trouble communicating over a network.

  • Can the "problem" VM ping its default gateway?

  • What does the arp cache on the "problem" VM look like when its trying to ping its default gateway (arp -a output)?

  • Thanks Evan, your idea if copying the VM lead me to the solution of my problems, see my answer.
    – IronGoofy
    May 12, 2010 at 21:05
  • Duplicate MAC addresses make for really, really funny things happening. It's a failure-mode that Ethernet wasn't built to handle gracefully. May 12, 2010 at 21:38

It seems that the problem was caused by copying the virtual machine which resulted in them having the same MAC address.

Here's how to change that:

  • open the VMs config file (*.vmx)
  • there will lines similar to this:
    ethernet0.generatedAddress = "00:0c:29:d6:fb:50"
    ethernet0.generatedAddressOffset = "0"
  • they have to be deleted (or commented out using #) and replaced by these:
    ethernet0.address = 00:50:56:xx:yy:zz
  • xx has to be in the range of 00 and 3F yy and zz can be any Hex number
  • Rather than statically assigning a MAC, just delete the lines beginning with: ethernet0.addressType, uuid.location, uuid.bios, ethernet0.generatedAddress, ethernet0.generatedAddressOffset When the VM is restarted you'll be prompted to generate a new UUID and a new MAC will be generated at that time. May 12, 2010 at 21:40

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