enabling cross-origin resource sharing on IIS7

Asked 17/9, 2012 at 11:40 Answered 12/8, 2022 at 8:54

Solved javascript iis-7 xmlhttprequest cors

101

I recently ran into with posting Javascript requests to another domain. By default XHR posting to other domains is not allowed.

Following the instructions from http://enable-cors.org/, I enabled this on the other domain.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
 <system.webServer>
  <httpProtocol>
    <customHeaders>
      <add name="Access-Control-Allow-Origin" value="*" />
      <add name="Access-Control-Allow-Methods" value="GET,PUT,POST,DELETE,OPTIONS" />
      <add name="Access-Control-Allow-Headers" value="Content-Type" />
    </customHeaders>
  </httpProtocol>
 </system.webServer>
</configuration>

enter image description here

Everything works fine now, however it is still return a 405 response before sending back the working 200 response.

Request URL:http://testapi.nottherealsite.com/api/Reporting/RunReport
Request Method:OPTIONS
Status Code:405 Method Not Allowed
Request Headersview source
Accept:*/*
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-GB,en-US;q=0.8,en;q=0.6
Access-Control-Request-Headers:origin, content-type, accept
Access-Control-Request-Method:POST
Connection:keep-alive
Host:testapi.nottherealsite.com
Origin:http://test.nottherealsite.com
Referer:http://test.nottherealsite.com/Reporting
User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1
Response Headersview source
Access-Control-Allow-Headers:Content-Type
Access-Control-Allow-Methods:GET,PUT,POST,DELETE,OPTIONS
Access-Control-Allow-Origin:*
Allow:POST
Cache-Control:private
Content-Length:1565
Content-Type:text/html; charset=utf-8
Date:Tue, 18 Sep 2012 14:26:06 GMT
Server:Microsoft-IIS/7.5
X-AspNet-Version:4.0.30319
X-Powered-By:ASP.NET

Update: 3/02/2014

There is a recently updated article in MSDN magazine. Detailing CORS Support in ASP.NET Web API 2.

http://msdn.microsoft.com/en-us/magazine/dn532203.aspx

Cerell answered 17/9, 2012 at 11:40 Comment(1)

it resolved my problem of getting false sort icon of jQuery bootgrid plugin want to load glyphicons-halflings-regular.woff from Bootstrap fonts folder – Keon 11/3, 2015 at 6:21

It is likely a case of IIS 7 'handling' the HTTP OPTIONS response instead of your application specifying it. To determine this, in IIS7,

Go to your site's Handler Mappings.
Scroll down to 'OPTIONSVerbHandler'.
Change the 'ProtocolSupportModule' to 'IsapiHandler'
Set the executable: %windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll

Now, your config entries above should kick in when an HTTP OPTIONS verb is sent.

Alternatively you can respond to the HTTP OPTIONS verb in your BeginRequest method.

    protected void Application_BeginRequest(object sender,EventArgs e)
    {
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");

        if(HttpContext.Current.Request.HttpMethod == "OPTIONS")
        {
            //These headers are handling the "pre-flight" OPTIONS call sent by the browser
            HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
            HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept");
            HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "1728000" );
            HttpContext.Current.Response.End();
        }

    }

Chummy answered 31/1, 2013 at 16:55 Comment(12)

I tried both method, but only BeginREquest method works for me. Thanks @Shah – Bibcock 28/11, 2013 at 11:21

For me, adding it to web.config in the same way as OP was the only way. Global.asax/BeginRequest did not work. – Subscribe 5/6, 2014 at 13:5

After 2 days of research, using the alternative solution based on Application_BeginRequest was the only way for me to fix the problem. I tried other methods using customHeaders (https://mcmap.net/q/75518/-http-options-request-on-azure-websites-fails-due-to-cors), removing OPTIONSVerbHandler handler, removing WebDAV module and handler (https://mcmap.net/q/75519/-cors-405-method-not-allowed) but none worked for me. Hope this will help others people. And thanks @Chummy for your answer ! – Dingess 15/10, 2014 at 8:34

Damn ASP.NET and IIS. Why should it be so hard to configure a simple concept like CORS? It's truly simple. Just read the W3C's specification. You can learn it in 10 minutes, and then you need 10 days to figure out how to configure it in ASP.NET, and IIS. – Insure 13/12, 2014 at 13:53

@Mendhak, you saved my life lol. Only thing I added was always HttpContext.Current.Response.AddHeader("Access-Control-Allow-Credentials", "true"); because of shared authentication cookie. – Waligore 3/2, 2015 at 16:59

@Saeed Neamati - so true, haha. Microsoft really has a convoluted way of doing things. – Waligore 3/2, 2015 at 17:0

Finally a solution which works ! After having spent like 8 hours trying to find a solution to this issue, finally came across this fix. You saved my 'arse' big time. Thanks ! – Ellipsoid 19/12, 2015 at 23:25

This did it for me. +1 – Dawson 13/3, 2018 at 21:20

After spending hours troubleshooting this, this is the ONLY solution that works. Our config was as follows: IIS 10 / CORS from a Chrome client. What did NOT work: changing the Web.config (added handlers with new verbs etc), changing the application.config. Note that we got it to work with Postman, with web.config changes, but not with a browser client. – Rockabilly 27/4, 2018 at 2:49

Can something like this be done for JavaScript of via web.config? – Morra 24/1, 2020 at 17:50

I had to add Authorization for the Access-Control-Allow-Headers HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept, Authorization"); – Alaric 2/10, 2020 at 3:53

it gives this error: IsapiHandler is not a default handler, please specify one from the list. and in the list there is no item with this name. – Bordure 5/1, 2022 at 23:48

I found the information found at http://help.infragistics.com/Help/NetAdvantage/jQuery/2013.1/CLR4.0/html/igOlapXmlaDataSource_Configuring_IIS_for_Cross_Domain_OLAP_Data.html to be very helpful in setting up HTTP OPTIONS for a WCF service in IIS 7.

I added the following to my web.config and then moved the OPTIONSVerbHandler in the IIS 7 'hander mappings' list to the top of the list. I also gave the OPTIONSVerbHander read access by double clicking the hander in the handler mappings section then on 'Request Restrictions' and then clicking on the access tab.

Unfortunately I quickly found that IE doesn't seem to support adding headers to their XDomainRequest object (setting the Content-Type to text/xml and adding a SOAPAction header).

Just wanted to share this as I spent the better part of a day looking for how to handle it.

<system.webServer>
    <httpProtocol>
        <customHeaders>
            <add name="Access-Control-Allow-Origin" value="*" />
            <add name="Access-Control-Allow-Methods" value="GET,POST,OPTIONS" />
            <add name="Access-Control-Allow-Headers" value="Content-Type, soapaction" />
        </customHeaders>
    </httpProtocol>
</system.webServer>

Sherillsherilyn answered 26/4, 2013 at 5:28 Comment(4)

Shah's IIS isapiHandler configuration didn't work, I didn't try the programming way though. However I also found the above WCF configuration in web.config did the trick. Chrome still sends OPTIONS and gets 405 the 1st time, but then it POST another request, which then is correct. – Moralez 14/5, 2013 at 5:35

It looks like current version of Chrome does no more take into account cors headers received on an response having an error http status. So it will no more go on in this case and perform the cross-domain request. This is a better behavior imho. – Arbiter 21/11, 2013 at 13:23

Thank you for this response. If you skimmed the response above do not forget to give the OPTIONSVerbHander read access as outlined above. – Tallbott 27/10, 2014 at 17:5

It is safer to specify a source. look: <add name="Access-Control-Allow-Origin" value="http://my.origin.host" /> – Pantywaist 15/11, 2015 at 15:34

I can't post comments so I have to put this in a separate answer, but it's related to the accepted answer by Shah.

I initially followed Shahs answer (thank you!) by re configuring the OPTIONSVerbHandler in IIS, but my settings were restored when I redeployed my application.

I ended up removing the OPTIONSVerbHandler in my Web.config instead.

<handlers>
    <remove name="OPTIONSVerbHandler"/>
</handlers>

Arsine answered 28/6, 2013 at 6:5 Comment(2)

For those who don't week with web.config everyday this goes inside "<system.webServer>" – Lollop 30/4, 2015 at 4:38

This answer helped me for MVC6 web api project deployed under IIS7. In production machine this option is working fine but as suggested above I had to delete it for the same project during migration on the other terminal! Thanks – Matazzoni 28/10, 2021 at 18:37

Elaborating from DavidG answer which is really near of what is required for a basic solution:

First, configure the OPTIONSVerbHandler to execute before .Net handlers.
1. In IIS console, select "Handler Mappings" (either on server level or site level; beware that on site level it will redefine all the handlers for your site and ignore any change done on server level after that; and of course on server level, this could break other sites if they need their own handling of options verb).
2. In Action pane, select "View ordered list..." Seek OPTIONSVerbHandler, and move it up (lots of clicks...).
You can also do this in web.config by redefining all handlers under <system.webServer><handlers> (<clear> then <add ...> them back, this is what does the IIS console for you) (By the way, there is no need to ask for "read" permission on this handler.)

Second, configure custom http headers for your cors needs, such as:

<system.webServer>
  <httpProtocol>
    <customHeaders>
      <add name="Access-Control-Allow-Origin" value="*"/>
      <add name="Access-Control-Allow-Headers" value="Content-Type"/>
      <add name="Access-Control-Allow-Methods" value="POST,GET,OPTIONS"/>
    </customHeaders>
  </httpProtocol>
</system.webServer>

You can also do this in IIS console.

This is a basic solution since it will send cors headers even on request which does not requires it. But with WCF, it looks like being the simpliest one.

With MVC or webapi, we could instead handle OPTIONS verb and cors headers by code (either "manually" or with built-in support available in latest version of webapi).

Ailey answered 21/11, 2013 at 14:1 Comment(1)

This worked for me. I don't like that every handler ends up redefined in the Web.config but alas it seems to be what I need to do to make our WCF services CORS enabled. +1 – Competency 24/6, 2015 at 17:45

It took Microsoft years to identify the gaps and ship an out-of-band CORS module to solve this problem.

Install the module from Microsoft
Configure it with snippets

as below

<configuration>
    <system.webServer>
        <cors enabled="true" failUnlistedOrigins="true">            
            <add origin="http://*" allowed="true" />
        </cors>
    </system.webServer>
</configuration>

In general, it is much easier than your custom headers and also offers better handling of preflight requests.

In case you need the same for IIS Express, use some PowerShell scripts I wrote.

Baisden answered 24/3, 2020 at 1:57 Comment(1)

Thank you! Using the IIS CORS module was the only way to resolve the CORS problem in my application. – Sorrel 5/2, 2021 at 7:58

The 405 response is a "Method not allowed" response. It sounds like your server isn't properly configured to handle CORS preflight requests. You need to do two things:

1) Enable IIS7 to respond to HTTP OPTIONS requests. You are getting the 405 because IIS7 is rejecting the OPTIONS request. I don't know how to do this as I'm not familiar with IIS7, but there are probably others on Stack Overflow who do.

2) Configure your application to respond to CORS preflight requests. You can do this by adding the following two lines underneath the Access-Control-Allow-Origin line in the <customHeaders> section:

<add name="Access-Control-Allow-Methods" value="GET,PUT,POST,DELETE" />
<add name="Access-Control-Allow-Headers" value="Content-Type" />

You may have to add other values to the Access-Control-Allow-Headers section based on what headers your request is asking for. Do you have the sample code for making a request?

You can learn more about CORS and CORS preflight here: http://www.html5rocks.com/en/tutorials/cors/

Harlequin answered 17/9, 2012 at 13:10 Comment(0)

With ASP.net Web API 2 install Microsoft ASP.NET Cross Origin support via nuget.

http://enable-cors.org/server_aspnet.html

public static void Register(HttpConfiguration config)
{
 var enableCorsAttribute = new EnableCorsAttribute("http://mydomain.com",
                                                   "Origin, Content-Type, Accept",
                                                   "GET, PUT, POST, DELETE, OPTIONS");
        config.EnableCors(enableCorsAttribute);
}

Cerell answered 3/2, 2014 at 22:15 Comment(1)

Do you know if there's anyway to programmatically set the first "ORIGIN" parameter of EnableCorsAttribute ? Let's say not here in the Register, but for each individual HTTP request that comes in. Detect the origin it's coming from, make sure it is OK (check against some list of approved ones) then return a response with Access-Allow-Control-Origin="thatdomain.com" ? @Cerell – Loria 8/1, 2016 at 15:19

Alsalaam Aleykum.

The first way is to follow the instructions in this link:

http://help.infragistics.com/Help/NetAdvantage/jQuery/2013.1/CLR4.0/html/igOlapXmlaDataSource_Configuring_IIS_for_Cross_Domain_OLAP_Data.html

Which corresponds to these configuration:

<handlers>
  <clear />
  <add name="OPTIONSVerbHandler" path="*" verb="OPTIONS" type="" modules="ProtocolSupportModule" scriptProcessor="" resourceType="Unspecified" requireAccess="Read" allowPathInfo="false" preCondition="" responseBufferLimit="4194304" />
  <add name="xamlx-ISAPI-4.0_64bit" path="*.xamlx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="4194304" />
  <add name="xamlx-ISAPI-4.0_32bit" path="*.xamlx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="4194304" />
  <add name="xamlx-Integrated-4.0" path="*.xamlx" verb="GET,HEAD,POST,DEBUG" type="System.Xaml.Hosting.XamlHttpHandlerFactory, System.Xaml.Hosting, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" modules="ManagedPipelineHandler" scriptProcessor=""
  resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="rules-ISAPI-4.0_64bit" path="*.rules" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64"
  responseBufferLimit="4194304" />
  <add name="rules-ISAPI-4.0_32bit" path="*.rules" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32"
  responseBufferLimit="4194304" />
  <add name="rules-Integrated-4.0" path="*.rules" verb="*" type="System.ServiceModel.Activation.ServiceHttpHandlerFactory, System.ServiceModel.Activation, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" modules="ManagedPipelineHandler"
  scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="xoml-ISAPI-4.0_64bit" path="*.xoml" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64"
  responseBufferLimit="4194304" />
  <add name="xoml-ISAPI-4.0_32bit" path="*.xoml" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32"
  responseBufferLimit="4194304" />
  <add name="xoml-Integrated-4.0" path="*.xoml" verb="*" type="System.ServiceModel.Activation.ServiceHttpHandlerFactory, System.ServiceModel.Activation, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" modules="ManagedPipelineHandler"
  scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="svc-ISAPI-4.0_64bit" path="*.svc" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64"
  responseBufferLimit="4194304" />
  <add name="svc-ISAPI-4.0_32bit" path="*.svc" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32"
  responseBufferLimit="4194304" />
  <add name="svc-Integrated-4.0" path="*.svc" verb="*" type="System.ServiceModel.Activation.ServiceHttpHandlerFactory, System.ServiceModel.Activation, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" modules="ManagedPipelineHandler" scriptProcessor=""
  resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="ISAPI-dll" path="*.dll" verb="*" type="" modules="IsapiModule" scriptProcessor="" resourceType="File" requireAccess="Execute" allowPathInfo="true" preCondition="" responseBufferLimit="4194304" />
  <add name="AXD-ISAPI-4.0_64bit" path="*.axd" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="PageHandlerFactory-ISAPI-4.0_64bit" path="*.aspx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="SimpleHandlerFactory-ISAPI-4.0_64bit" path="*.ashx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="WebServiceHandlerFactory-ISAPI-4.0_64bit" path="*.asmx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="HttpRemotingHandlerFactory-rem-ISAPI-4.0_64bit" path="*.rem" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="HttpRemotingHandlerFactory-soap-ISAPI-4.0_64bit" path="*.soap" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="aspq-ISAPI-4.0_64bit" path="*.aspq" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness64"
  responseBufferLimit="0" />
  <add name="cshtm-ISAPI-4.0_64bit" path="*.cshtm" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="cshtml-ISAPI-4.0_64bit" path="*.cshtml" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="vbhtm-ISAPI-4.0_64bit" path="*.vbhtm" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="vbhtml-ISAPI-4.0_64bit" path="*.vbhtml" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="TraceHandler-Integrated-4.0" path="trace.axd" verb="GET,HEAD,POST,DEBUG" type="System.Web.Handlers.TraceHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="WebAdminHandler-Integrated-4.0" path="WebAdmin.axd" verb="GET,DEBUG" type="System.Web.Handlers.WebAdminHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="AssemblyResourceLoader-Integrated-4.0" path="WebResource.axd" verb="GET,DEBUG" type="System.Web.Handlers.AssemblyResourceLoader" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="PageHandlerFactory-Integrated-4.0" path="*.aspx" verb="GET,HEAD,POST,DEBUG" type="System.Web.UI.PageHandlerFactory" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="SimpleHandlerFactory-Integrated-4.0" path="*.ashx" verb="GET,HEAD,POST,DEBUG" type="System.Web.UI.SimpleHandlerFactory" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="WebServiceHandlerFactory-Integrated-4.0" path="*.asmx" verb="GET,HEAD,POST,DEBUG" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" modules="ManagedPipelineHandler"
  scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="HttpRemotingHandlerFactory-rem-Integrated-4.0" path="*.rem" verb="GET,HEAD,POST,DEBUG" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory, System.Runtime.Remoting, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
  modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="HttpRemotingHandlerFactory-soap-Integrated-4.0" path="*.soap" verb="GET,HEAD,POST,DEBUG" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory, System.Runtime.Remoting, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
  modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="aspq-Integrated-4.0" path="*.aspq" verb="GET,HEAD,POST,DEBUG" type="System.Web.HttpForbiddenHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="cshtm-Integrated-4.0" path="*.cshtm" verb="GET,HEAD,POST,DEBUG" type="System.Web.HttpForbiddenHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="cshtml-Integrated-4.0" path="*.cshtml" verb="GET,HEAD,POST,DEBUG" type="System.Web.HttpForbiddenHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="vbhtm-Integrated-4.0" path="*.vbhtm" verb="GET,HEAD,POST,DEBUG" type="System.Web.HttpForbiddenHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="vbhtml-Integrated-4.0" path="*.vbhtml" verb="GET,HEAD,POST,DEBUG" type="System.Web.HttpForbiddenHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0"
  responseBufferLimit="4194304" />
  <add name="ScriptHandlerFactoryAppServices-Integrated-4.0" path="*_AppService.axd" verb="*" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" modules="ManagedPipelineHandler"
  scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="ScriptResourceIntegrated-4.0" path="*ScriptResource.axd" verb="GET,HEAD" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" modules="ManagedPipelineHandler"
  scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="4194304" />
  <add name="AXD-ISAPI-4.0_32bit" path="*.axd" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="PageHandlerFactory-ISAPI-4.0_32bit" path="*.aspx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="SimpleHandlerFactory-ISAPI-4.0_32bit" path="*.ashx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="WebServiceHandlerFactory-ISAPI-4.0_32bit" path="*.asmx" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="HttpRemotingHandlerFactory-rem-ISAPI-4.0_32bit" path="*.rem" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="HttpRemotingHandlerFactory-soap-ISAPI-4.0_32bit" path="*.soap" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script"
  allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="aspq-ISAPI-4.0_32bit" path="*.aspq" verb="*" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false" preCondition="classicMode,runtimeVersionv4.0,bitness32"
  responseBufferLimit="0" />
  <add name="cshtm-ISAPI-4.0_32bit" path="*.cshtm" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="cshtml-ISAPI-4.0_32bit" path="*.cshtml" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="vbhtm-ISAPI-4.0_32bit" path="*.vbhtm" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="vbhtml-ISAPI-4.0_32bit" path="*.vbhtml" verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="TRACEVerbHandler" path="*" verb="TRACE" type="" modules="ProtocolSupportModule" scriptProcessor="" resourceType="Unspecified" requireAccess="None" allowPathInfo="false" preCondition="" responseBufferLimit="4194304" />
  <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
  <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG" type="" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG" type="System.Web.Handlers.TransferRequestHandler" modules="ManagedPipelineHandler" scriptProcessor="" resourceType="Unspecified" requireAccess="Script" allowPathInfo="false"
  preCondition="integratedMode,runtimeVersionv4.0" responseBufferLimit="0" />
  <add name="StaticFile" path="*" verb="*" type="" modules="StaticFileModule,DefaultDocumentModule,DirectoryListingModule" scriptProcessor="" resourceType="Either" requireAccess="Read" allowPathInfo="false" preCondition="" responseBufferLimit="4194304"
  />
</handlers>

The second way is as to respond to the HTTP OPTIONS verb in your BeginRequest method.

  protected void Application_BeginRequest(object sender, EventArgs e)
{
    HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
    if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
    {
        HttpContext.Current.Response.AddHeader("Access-Control-Request-Method", "GET ,POST, PUT, DELETE");

        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Origin,Content-Type, Accept");
        HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "86400"); // 24 hours
        HttpContext.Current.Response.End();
    }
}

Malraux answered 8/9, 2015 at 20:36 Comment(0)

The solution for me was to add :

<system.webServer>
    <modules runAllManagedModulesForAllRequests="true">
      <remove name="WebDAVModule"/>
    </modules>
</system.webServer>

To my web.config

Cariole answered 5/4, 2016 at 20:55 Comment(0)

One thing that has not been mentioned in these answers is that if you are using IIS and have sub applications with their own separate web.config, you may need to have a web.config in the parent directory containing the following code.

<httpProtocol>
  <customHeaders>
    <add name="Access-Control-Allow-Origin" value="*"/>
    <add name="Access-Control-Allow-Headers" value="Content-Type"/>
    <add name="Access-Control-Allow-Methods" value="POST,GET,OPTIONS"/>
  </customHeaders>
</httpProtocol>

Distinguishing answered 12/7, 2017 at 17:0 Comment(0)

On our server OPTIONS verb was not enabled. This fixed it and it took one minute

To configure unlisted HTTP verbs by using the UI Open IIS Manager and select the level for which you want to configure request filter. In Features View, double-click Request Filtering. Select the HTTP Verbs tab. In the Actions pane, click either Allow Verb or Deny Verb. Enter the verb in the box, and then click OK.

Slocum answered 12/8, 2022 at 8:54 Comment(0)

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