Scott Forsyth's Blog

There are also some other important information available for administrator. As given in,

bradwilson.typepad.com/.../diagnosing-aspnet-mvc-problems.html

weblogs.asp.net/.../monitoring-asp-net-mvc-application.aspx

May be you will cover these information in your next videos.

The problem is that for a load balancer requests to a url and url/siteserverdetails.axd can come from different nodes. I usually use Fiddler and insert host name and IP in an "X-" header using URL Rewrite outbound rules.

Advantage - no need to install anything because you already have URL Rewrite on your Web Farm nodes. All done by appcmd.

Disadvantage - a potential slight overhead (never observed) for URL Rewrite processing

REM Next line is a workaround because URL Rewrite needs something to "rewrite" it can't add a header to Http Response. Adding custom header X-Responding-Host which can be seen in Fiddler and any network monitoring tools for every response

appcmd set config  -section:system.webServer/httpProtocol /+"customHeaders.[name='X-Responding-Host',value='*']" /commit:apphost

REM create outbound rewrite rule for the server

appcmd set config  -section:rewrite/outboundRules /+"[name='X-Responding-Host',patternSyntax='Wildcard',stopProcessing='True']" /commit:apphost

REM add condition and action to the rule

REM None rule syntax for matching response header name, it needs prefix "RESPONSE_" and all dashes replaced with underscore

appcmd set config  -section:rewrite/outboundRules /[name='X-Responding-Host'].conditions.trackAllCaptures:"False" /[name='X-Responding-Host'].match.serverVariable:"RESPONSE_X_Responding_Host" /[name='X-Responding-Host'].match.pattern:"*" /[name='X-Responding-Host'].action.type:"Rewrite" /[name='X-Responding-Host'].action.value:"{SERVER_NAME}/{LOCAL_ADDR}" /commit:apphost

The above adds the following in applicationHost.config

in <configuration><system.webServer>

under <httpProtocol><customHeaders>

<add name="X-Responding-Host" value="*" />

and under <rewrite><outboundRules>

               <rule name="X-Responding-Host" patternSyntax="Wildcard" stopProcessing="true">

                   <match serverVariable="RESPONSE_X_Responding_Host" pattern="*" />

                   <conditions trackAllCaptures="false" />

                   <action type="Rewrite" value="{SERVER_NAME}/{LOCAL_ADDR}" />

               </rule>

Thank you for the tip Scott! Great video!

In my previous comment I included a small fragment of our deployment documentation that I wrote for our admins, so it was a little verbose :) The {SERVER_NAME} variable was the best solution I could find a few months ago. Maybe IIS team will add the machine name variable eventually until then we will be using your awesome ServerNameVariableProvider. {SERVER_NAME} works well though in many corporate intranet web farm scenarios' when all applications (like in our case) are running under a single default "catch-all" IIS site and load balancer sends all requests to the nodes using their machine names. Usually I add machine name as an X header when I set up a new IIS server like this:

appcmd set config  -section:system.webServer/httpProtocol /+"customHeaders.[name='X-Responding-Host',value='%COMPUTERNAME%']" /commit:apphost

But with Microsoft Web Farm framework that does not work because it replicates configuration among the nodes so I had to use URL Rewrite.

I'm also a big fan of URL Rewrite and ARR, I wish they were better documented :) - many thanks for bloging about it, much appreciated!