I have a TCP connection issue as follows.

The setup:

VMWare Virtual Machine: Windows Server 2008 R2 DataCenter SP1, IP:, DG: Host Machine: Windows 7 Professional SP1, IP:, DG:

  • Firewall disabled on both machines

  • Virtual Machine Setting Network Adapter = Bridged Mode

  • No ip address or mac address clash ("arp -a" looks OK for this mapping)

  • Wireshark running on both VM and host machine

Linux Box 2.6.18-194.e15, IP:, DG:

  • Firewall disabled

VM and Linux box on different subnets but all traffic passed through default gateway ( & in both directions OK

The Issue:

Can't make TCP connection from Linux box to VM

On Linux box if I do: traceroute -T -p5066

the SYN messages are picked up on the Wireshark running on the Host Machine ( and not on the VM ( so they don't reach the VM.

There is definitely an application on listening for TCP on port 5066 so it would respond if the SYN got to the VM.

I can ping from Linux and I can do traceroute -I (which uses ICMP like ping) but TCP doesn't work.

I can make a TCP connection the other way from the VM to the Linux box so I don't think there's any issue with the mapping between the virtual network adpater and the host physical network adapter.

The VM can ping itself if I ping, the VM and the host can ping each other and I can file browse in both directions between the VM and the host.

I have uninstalled and reinstalled the network adapter on the VM and also TCP/IP for IPv4 and still no luck.

Any suggestions for other things to try ?


  • 1
    A very detailed first post, thanks for that. Can you elaborate a little more on what router you are using? Are there any firewall rules between subnets? – Alex Berry Aug 7 '14 at 14:39
  • 3
    Some similar problems have turned out to be caused by dysfunctional TCP checksum offloading. So disabling TCP checksum offloading would be worth trying. Though I must say the symptoms sounds a bit more like a firewall problem than a TCP checksum offloading problem. – kasperd Aug 7 '14 at 14:58
  • Thanks kasperd, disabling the TCP checksum offloading works. Thanks very much. – user3416108 Aug 7 '14 at 17:01

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