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WIndows Server 2012 LBFO /LACP - DNS resolution fails or is slow. RRS feed

  • Question

  • Has anyone had a problem setting up LBFO with LACP where DNS resolution to even local resources stops working? I am experiencing this issue.

    I have LBFO configured on my Windows Server 2012 with LACP and Address Hash. I have two NICs in the LBFO team each connected to a different switch that I am told by the Network group is configured as a single logical switch. (Since LACP is switch dependent). Starting out, DNS resolution works fine. After a day or so, sometimes within minutes, DNS resolution to even local resources either time out or is extremely slow. If I disable one of the NICS in the LBFO team, DNS resolution works fine immediately. If I re-enable the NIC where both are enabled, DNS times out or is slow to resolve. If I delete the LBFO and reconfigure, DNS works for a little while but eventually malfunctions again. If I disable the LBFO interface and re-enable, DNS resolution works again. Both NICS are on the same VLAN behind an BigIP LTM with a single VIP.

    The LTM does not act in anyway as a firewall. What is weird is that if I see the malfunction with DNS resolution, all I have to do is disable one NIC in the team and DNS works fine. Re-enabling the NIC immediately brings back the problem. It does not matter which NIC of the team I disable. I contacted our Network team to inquire about the fact that LACP is switch dependent but I was told that the switches operate as a single logical switch and thereby meets the switch dependent criteria. We currently have other servers on LACP using Hyper-V rather than Address Hash and there are no problems. But my server is not a Hyper-V server. Can anyone help?

    Monday, October 14, 2013 3:21 PM

Answers

  • The official answer to solve the problem was that there is a bug in LBFO for Server 2012 and I had to upgrade the server to 2012 R2 which fixed the issue.
    • Marked as answer by WBrianBritt Wednesday, April 22, 2015 6:11 PM
    Wednesday, April 22, 2015 6:11 PM

All replies

  • I opened a case with MS PSS to resolve. We have taken Network traces all the way through the switch and are analyzing. More info to come as we seek resolution.

    Brian

    Monday, March 24, 2014 1:16 PM
  • The official answer to solve the problem was that there is a bug in LBFO for Server 2012 and I had to upgrade the server to 2012 R2 which fixed the issue.
    • Marked as answer by WBrianBritt Wednesday, April 22, 2015 6:11 PM
    Wednesday, April 22, 2015 6:11 PM