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Let me start by saying, I am winging here as I am a complete Linux n00b. I have a requirement that I need to have a CentOS box running in ...
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  1. #1
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    CentOS 6 and Hyper-V


    Let me start by saying, I am winging here as I am a complete Linux n00b. I have a requirement that I need to have a CentOS box running in windows hyperv. I went through and installed the OS with no problems, then installed the Linux Integration Components from MS website. Currently the Linux VM is showing that is has a network adapter, as when i do ifconfig it shows me adapter information and a hardware address.

    If I tell the VM to connect and get an IP address it will communicate with the switch (we are using port security on our cisco switches and I can see the mac address propagate to the switch) but will never get an IP address. I tried assigning it manually but didnt have any luck with that either, as the manually assigned IP can't communicate. I am sure it is something stupid that I have missed, but after 2 days I am pulling my hair out. I appreciate any help I can get and can provide any information that you may need.

    I am running:
    CentOS Release 6.3

  2. #2
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    IPs are provided by routers or other devices that broadcast DHCP, not switches.

    If you are using VLANs on your switch, make sure the VLAN has access to the VLAN the router is on. Also, if your switch port is tagged with multiple VLANs, make sure your Windows interfaces are tagged or you Centos interface is you have some kind of NIC pass-through setup.

    Are there other VMs on this host? Can you ping those other VMs? Unfortunately, that's as much help as I'm going to be able to provide with information given.

  3. #3
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    vlans are a possible cause, as outlined by mizzle.

    Another one is wrong networkcard config on the hyperv side.
    Are the virtualized NICs bridged, nated, or in their own network?
    You must always face the curtain with a bow.

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    The virtual interface in question works fine if connected to another VM, so I am sure that isnt the problem. The DHCP server and the Linux box are both in the same VLAN, but all of my VLAN's have access to the "server" VLAN the dhcp host resides in.

    The network card on the HyperV host side is bridged.

  5. #5
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    Quote Originally Posted by RoryHamaker View Post
    The virtual interface in question works fine if connected to another VM, so I am sure that isnt the problem. The DHCP server and the Linux box are both in the same VLAN, but all of my VLAN's have access to the "server" VLAN the dhcp host resides in.

    The network card on the HyperV host side is bridged.
    If your traffic is getting to the switch, and not getting to the DHCP server, I am still leaning towards vlans. It's always the darn vlans.
    Or..your DHCP server is only broadcasting to MACs in a certain range or set, and is refusing to supply the IP.
    If you configure you adapter with manual settings, you should be able to connect to other hosts on the same subnet.

  6. #6
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    The DHCP server is blindly handing out addresses, we dont use any MAC filtering. We are using cisco port security and the Linux's mac address is registered correctly. I can actually start a PXE boot from this virtual box (i used that just to check the networking) and it works fine which tells me the system is getting an IP during a pxe attempt so the port should be able to contact the DHCP server and get an address using its MAC address.

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