I'm trying to set up my IIS server as an origin server for a CDN. I have solved some issues already for example that IIS doesn't give gziped content to proxies (if they have the via header) and also that frequentHitThreshold problem.
My CDN supplier pointed out that another problem with IIS is that it doesn't return a "Vary" header if the client doesn't request the content gziped. According to them the problem is that if for some reason the first client that request the content doesn't want the content gziped the CDN then doesn't request a new version of the file since the Vary header doesn't indicate that it should return two different files depending on "Accept-Encoding".
My only solution so far is to add "Vary: Accept-Encoding" as a custom header but since IIS automatically add this vary header when gziped is requested so i end up with multiple values like "Vary: Accept-Encoding, Accept-Encoding".
Anyone have any solution to this? Or can confirm that it's a real issue.
This is a real issue. IIS gzip module overwrites existing Vary headers. Please vote on this MS Connect issue. Related article here.
This issue is now addressed by an official patch to IIS. To download and further info, visit http://support.microsoft.com/kb/2877816
Erez Benari, IIS PM
Related
I have a website which sits on a non-public domain and is delivered via a proxy through on a different domain. We're having some trouble with caching of content - this is an Umbraco site and making changes updates the pages if you hit the domain directly, but not through the proxy.
I've been informed that the proxy honours response headers and setting an eTag would fix the issue. Having looked into this I can see that IIS sets the eTag by default, and I can see this is working on static content i.e. .js, .css files like so:
However, if I visit a page on the site, for example /uk/products/product I don't see the eTag header.
Is this expected behaviour, should it only be working with those static content files or can I set this on the page to tell the proxy that it should recache?
The ETag HTTP response header is an identifier for a specific version of a resource. It lets caches be more efficient and save bandwidth, as a web server does not need to resend a full response if the content has not changed. Additionally,etags help prevents simultaneous updates of a resource from overwriting each other ("mid-air collisions").
If the resource at a given URL changes, a new Etag value must be generated.
Static content does not change from request to request. The content that gets returned to the Web browser is always the same. Examples of static content include HTML, JPG, or GIF files.
IIS automatically caches static content (such as HTML pages, images, and style sheets), since these types of content do not change from request to request. IIS also detects changes to the files when you make updates, and IIS flushes the cache as needed.
to enable caching in iis you could use iis output caching feature:
1)open iis manager. select site.
2)select the output caching feature from the middle pane.
3)select edit feature setting from the middle pane.
4)check the enable cache and enable kernel cache box and click ok.
if you want to set the ETag as blank you could also do by adding below code in web.config file:
<httpProtocol>
<customHeaders>
<add name="ETag" value="" />
</customHeaders>
</httpProtocol>
refer this below article for more detail:
Caching
To use or not to use ETag, that is the question.
Configure IIS Output Caching
I've read that IIS after version 7 automatically enables E-tags, however, I ran a Pingdom speed test and the report advised me to enable E-tags. I'm not sure that report is accurate, or the information I read about IIS 7 and newer may not be correct.
I need to add a custom http header to every http response from my IIS 8.5, but only for specific file types (css, js and html).
I've tried this solution
Add custom header based on file type, but it seems outdated, and I'm getting errors for bad web.config file.
How it can be done on IIS 8.5?Any help will be appreciated.
Solution on this link still working Add custom header based on file type for your problem.
You weren't able to use it because you need to install URL Rewrite module for IIS.
Please go to https://www.iis.net/downloads/microsoft/url-rewrite , download, install it and then restart IIS. After this steps error about bad web.config file should gone
I am facing an issue where server header information is showing up in IIS. I know by using URL rewrite module and creating outbound rule will resolve the issue. Problem here is when i am checking individual severs i am seeing server header information as Server:-Microsoft-IIS/7.5. and when i am checking LB URL i am seeing server:- IA Web server. not sure from where this text is coming up.I checked the web.config file but the entry for witting own server information is not present in an tag. Also one more information i have akamai implemented after the web servers. Could some one help in this context.
This is added by IIS Server. Adding outbound URL-Rewrite rule is the best way to go as adding a custom HTTPModule to remove headers or through global.asax.cs as explained in this answer won't work for static files.
See detailed blog here - https://blogs.msdn.microsoft.com/varunm/2013/04/23/remove-unwanted-http-response-headers/
I faced a problem.
When you add multiple Set-Cookie headers to the response
headers.Add("Set-Cookie", "a=b;Path=/;");
headers.Add("Set-Cookie", "c=d;Path=/;");
actually they are combined and only one header is sent with comma-separated cookies
Set-Cookie: a=b;Path=/;,c=d;Path=/;
According to RFC2109 it is a valid syntax.
But it is not according to RFC6265, which deprecates RFC2109
Moreover latest browsers does not support this comma-separated syntax as well. Tested on IE9, Firefox 13 and Google Chrome 20.
All of these browsers took first cookie only.
Please see the sample project below
https://github.com/mnaoumov/cookie-bug/
I want to find some workaround.
I expect to have two different Set-Cookie headers.
I tried to write some MessageInspector to rewrite HTTP headers. I could not find how to access that headers.
Any ideas?
P.S. Used technology: Web API
According to answer on codeplex (http://aspnetwebstack.codeplex.com/workitem/288) this issue is known issue and related to WCF self-hosting and should be fixed by moving to IIS hosting.
This is WCF 4 issue which marked as won't fix.
Found another question with the same outcome WCF 4.0 Cookie Only First is Recorded by Browser.
You can use the HttpContext.Current.Response.SetCookie
using System.Web;
HttpCookie foo = new HttpCookie("foo", "true");
HttpContext.Current.Response.Cookies.Add(foo);
HttpCookie bar = new HttpCookie("bar", "true");
HttpContext.Current.Response.Cookies.Add(bar);
This will add multiple set-cookies header in the response.
Edit: also, you should add the
<serviceHostingEnvironment multipleSiteBindingsEnabled="true" aspNetCompatibilityEnabled="true"/>
in your web.config
Our IIS server has Dynamic and Static HTML Compression enabled, but when I browse to our website and view the Response Headers in Fiddler, I only see the "Content-Encoding: gzip" header for one resource (a flash file).
Why would the other response types not have this header? Does it mean that compression is NOT working for the other responses?
The only way to be 100% sure that compression is active is to compare the size of the downloaded resource against the original file on the server. The network tab of the Firebug extension can help you here.
It looks like our company network was actually stripping out the Content-Encoding header. (I have no idea why). When I browse from home the gzipping seems to work fine. This post on StackExchange.com helped me figure it out.