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Problem with VLAN Trunking within RHEL6.6 VM on Hyper-V 2012 R2? RRS feed

  • Question

  • Hello,

    I'm wondering if there is a known issue with using a "trunk" mode interface within a RHEL6.6 VM?  I found the following article:

    Where note 1 reads:

    • "For this specific RHEL/CentOS release, VLAN tagging may not work when used in conjunction with trunk mode".

    I've been fighting with this for the better part of a day and can't figure out what I'm doing wrong.  I have a RHEL 6.6 VM with two NICs.  The first NIC is a standard access mode NIC - no problems there.

    The second NIC has been set up as follows (via PowerShell):

    •     $a=Get-VmNetworkAdapter -VMName "My VM"
    •     Set-VMNetworkAdapterVlan -Trunk -VmNetworkAdapter $a[1] -AllowedVlanIdList 101-105 -NativeVlanId 1

    Note that the physical switch and switchports are configured to send tagged packets for these VLANs as well.

    I then set up a VLAN (eth1.102) based interface in the VM ... and never receive any traffic on it.

    What I've observed is that:

    1. A VM on the same physical host using the same virtual switch can communicate with the VM on the tagged VLAN
    2. A pcap of the "eth1" interface (to which eth1.102 is bound) shows traffic for VLANs 101 through 105 arriving ... I just never see the traffic for VLAN 102 forwarded to the eth1.102 interface
    3. An identical network configuration using Ubuntu 14.04.01 LTS works exactly as expected

    It's this last point that has me wondering if the problem is with RHEL and not Hyper-V (or the physical/virtual switches involved).

    I'm curious if anybody else has seen this behavior or, if RHEL 6.x is working for you, if you're using Intel or Broadcom NICs on the physical Hyper-V host?

    Thanks,

    Sunday, February 1, 2015 11:17 PM

Answers

  • This is indeed a known issue with RHEL.   There's a bug open with Red Hat on the issue, and our understanding is that they have a fix in progress that will be part of a RHEL 6.6 update.  You might inquire with Red Hat regarding their bugzilla #1135347.

    Michael Kelley, Lead Program Manager, Open Source Technology Center

    • Marked as answer by dln_nospm Wednesday, February 4, 2015 12:22 AM
    Tuesday, February 3, 2015 10:13 PM
    Moderator

All replies

  • This is indeed a known issue with RHEL.   There's a bug open with Red Hat on the issue, and our understanding is that they have a fix in progress that will be part of a RHEL 6.6 update.  You might inquire with Red Hat regarding their bugzilla #1135347.

    Michael Kelley, Lead Program Manager, Open Source Technology Center

    • Marked as answer by dln_nospm Wednesday, February 4, 2015 12:22 AM
    Tuesday, February 3, 2015 10:13 PM
    Moderator
  • Thanks Michael.  At least I'm not going crazy.  In the end, I just went with Ubuntu - works very well.

    Thanks again.

    Wednesday, February 4, 2015 12:22 AM