I'm working with 2 machines, one running Ubuntu 14.04 and the other running Windows 7. The IT team has assigned me several IP addresses (xxx.xx.79.20 to xxx.xx.79.24) and I am trying to set static IP for the 2 machines.

The Ubuntu machine works well with any IP in the list, but the Windows machine work with none of them (I'm sure the subnet mask, gateway and DNS are correct). What makes me more confusing is, I tried another address on the same subnet (xxx.xx.79.3) on the Windows machine and it works! One might explain this by saying the IP addresses in the list are all used by other users, but why my Ubuntu machine could use them?

A few more thing I noticed: when pinging from Ubuntu to the IP's in the list, the command has no output, while pinging to xxx.xx.89.3, ping outputs "host unreachable" for each packet sent.

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    What do you mean by "it doesn't work"? What subnet mask are you using? What gateway? – Paul Feb 13 '15 at 2:39
  • I wonder if the issue is one of the switches being in different VLANS, or possibly mac filtering on the switch or some such. Can you advise the setup with respect of switches, and how you did the testing with respect of machines plugging into switch ports. If you have a spare unmanaged switch you might want to plug the uplink, linux box and windows box into it and see what happens - that may provide insite as to if the problem is related to the switch. – davidgo Feb 13 '15 at 5:49
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    Why don't you get your IT team to fix the issue? – DavidPostill Feb 13 '15 at 6:34
  • @Paul By "It doesn't work" I mean after setting the IP, Windows will report IP Address conflict (the IP is different from the one used on the Linux machine, of course), and the machine have no access to the Internet, as well as local network. As I've mentioned I am sure the subnet mask, gateway and DNS setting is correct. If I apply the same setting on the Ubuntu machine, it works all fine. – qddpx Feb 13 '15 at 17:55

Ubuntu differs from Windows due to the fact that it supports ucarp which does the following:

ucarp allows a pair of hosts to share common IP addresses in order to provide automatic failover of an address from one machine to another.


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