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IIS 8 NLB LoopBack Issues RRS feed

  • Question

  • User-1693112158 posted

    Hi All,

    I am attempting to load balance an IIS 8 website with a brocade load balancer.  The load balancer has been configured with the VIP which we have also added to the KM-TEST loopback adapter running on server 2012.

    When I attempt to access the website directly using http://servername.company.com it works fine, but when I try to access it using the web address ie. http://contoso.com it fails.  Internet explorer returns "Internet Explorer cannot display the webpage".  I have run netsh to check the incoming ports and can see the connection is establishing with the server, but it seems like IIS in not listening on the virtual address.  The website binding has been configured for http, all unassigned, and set to listen on port 80; we have even tried setting the port to 8080 instead.  I have turned off the windows firewall to ensure that this was not causing the issue.

    I have run the following commands, as required for the loopback adaper to work.  Plus, I have disabled the loopbackcheck in registry.

    netsh interface ipv4 set interface "LAN" weakhostreceive=enabled
    netsh interface ipv4 set interface "NLB loopback" weakhostreceive=enabled
    netsh interface ipv4 set interface "NLB loopback" weakhostsend=enabled

    Can anyone explain why this might not be working.  If you require further information please let me know?

    Any help would be much appreciated.

    Regards

    Barry

    Friday, April 26, 2013 10:44 AM

Answers

  • User-1731511703 posted

    Hi Barry,

    I haven't set up DSR on a set of load balanced servers since Windows 2008 so there might be something different that I'm not aware of.  Here are the key points that I had to do:

    1) set weakhostsend and weakhostreceive on both the NIC and the loopback adapter
    2) disable automatic metric on the loopback adapter
    3) add the VIP and subnet mask only to the loopback adapter

    The reason you could be getting an error and not being able to see the page is that it might be disabled/down on the brocade.  The next step is to see what kind of health check the brocade does and look for that in the logs for the site.  It should be returning an acceptable status code to the brocade.  Note that often by default these health checkes are set for 200 - 299 status codes and a redirect on the site with a 301 or 302 status code will also bring down the VIP.

    • Marked as answer by Anonymous Tuesday, September 28, 2021 12:00 AM
    Wednesday, May 1, 2013 3:25 PM

All replies

  • User-1731511703 posted

    The first thing that stands out to me is that you didn't mention anything about the Interface Metric on the Loopback Adapter.  Go into advanced properties and uncheck the box for automatic metric and set this to something like 254.

    Another thing to check is the health test.  Most hardware load balancers send a HEAD request to the nodes to determine if they are up.  You should be able to see those logged in the site's logs.  I recommend disabling health tests when initially setting up a web farm of servers like this using direct server return to make it easier to troubleshoot.

    Wednesday, May 1, 2013 11:33 AM
  • User-1693112158 posted

    Hi Rick,

    Firstly, thanks for your reply.

    I have tried configuring a metric of 200, but I forgot to include this information in my previous post.  This did not help.

    Do you have any other idea's what I could try?

    Regards

    Barry

    Wednesday, May 1, 2013 2:32 PM
  • User-1731511703 posted

    Hi Barry,

    I haven't set up DSR on a set of load balanced servers since Windows 2008 so there might be something different that I'm not aware of.  Here are the key points that I had to do:

    1) set weakhostsend and weakhostreceive on both the NIC and the loopback adapter
    2) disable automatic metric on the loopback adapter
    3) add the VIP and subnet mask only to the loopback adapter

    The reason you could be getting an error and not being able to see the page is that it might be disabled/down on the brocade.  The next step is to see what kind of health check the brocade does and look for that in the logs for the site.  It should be returning an acceptable status code to the brocade.  Note that often by default these health checkes are set for 200 - 299 status codes and a redirect on the site with a 301 or 302 status code will also bring down the VIP.

    • Marked as answer by Anonymous Tuesday, September 28, 2021 12:00 AM
    Wednesday, May 1, 2013 3:25 PM