On Ie CSS Font-Face Works Only When Navigating Through Inner Links

On IE CSS font-face works only when navigating through inner links

I found a solution but I cannot see the reason why it works (well, only one reason - it's IE :D).

What I did was to put the same site on Apache and test again. On Apache the fonts worked fine even when using Refresh button. Then in the network inspector I saw that Apache is returning 304 instead of 200 for the eot file and it hit me - so it's caching issue. I went to my ASP.NET app and sure enough - for security reasons (and also to avoid caching AJAX requests) someone had disabled every caching you could imagine:

        // prevent caching for security reasons
        HttpContext.Current.Response.Cache.SetAllowResponseInBrowserHistory(false);
        HttpContext.Current.Response.Cache.SetExpires(DateTime.UtcNow.AddDays(-1));
        HttpContext.Current.Response.Cache.SetValidUntilExpires(false);
        HttpContext.Current.Response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
        HttpContext.Current.Response.Cache.SetNoServerCaching();

        // do not use any of the following two - they break CSS fonts on IE
        HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
        HttpContext.Current.Response.Cache.SetNoStore();

As soon as I commented out the last two lines of code, suddenly fonts started to work without problems on IE. So I guess the answer is: IE cannot load the font if it is not cached. I have no idea why the problem happens only when refreshing/navigating back, though.

Edit - Alternative solution

Instead of commenting those last two lines

    // do not use any of the following two - they break CSS fonts on IE
    HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
    HttpContext.Current.Response.Cache.SetNoStore();

Change the SetAllowResponseInBrowserHistory to true instead:

HttpContext.Current.Response.Cache.SetAllowResponseInBrowserHistory(true);

This should still allow no-cache with the exception of back and forward navigation as I understand it.
MSDN - SetAllowResponseInBrowserHistory Method

@font-face not working locally but works when linked externally

local() accepts locally installed fonts' system identifier, not path to file, see: https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face#specifying_local_font_alternatives

@Font-Face won't load via https in IE

So, I just figured out a way that is working for IE, Safara, Firefox and Chrome as far as I can see.

Since all the things I tried did not work out, I was trying to find a way that could "embed" the fonts eitherway to my websites, to my CSS or to my server. Added the font to my server wasn't an option according to my server-guy so I decided to get back to Font-Squirrel and see if there was an option they offered in converting the fonts.

I reuploaded my fonts en chose the export mode. Somewhere around the bottom of the settings fields it says "Base64 Encode", luckily I knew what this meant (I can imagine someone who doesn't easily looks over this option) so I genereted my CSS files with base64 embdedded fonts.

This works flawlessly. Ofcourse this made my CSS files some kb's bigger (5kb vs 129kb). But I don't see a big adventage of 100kb extra with the current internet connections.

Just to compare, non base64 encoded CSS:

@font-face {
    font-family: 'ProximaNovaSemibolds';
    src: url('../font-face/proximanova-semibold-webfont.eot');
    src: url('../font-face/proximanova-semibold-webfont.eot?#iefix') format('embedded-opentype'),
         url('../font-face/proximanova-semibold-webfont.woff') format('woff'),
         url('../font-face/proximanova-semibold-webfont.ttf') format('truetype'),
         url('../font-face/proximanova-semibold-webfont.svg#ProximaNovaSemibold') format('svg');
    font-weight: normal;
    font-style: normal;
}

Base64 encoded CSS:

@font-face {
    font-family: 'ProximaNovaBold';
    src: url('proximanova-bold-webfont-webfont.eot');
    }

@font-face {
    font-family: 'ProximaNovaBold';
    src: url(data:application/x-font-woff;charset=utf-8;base64,d09GRgABAAAAAF+8ABMAAAAArzAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAABGRlRNAAABqAAAABwAAAAcYT+YZ0dERUYAAAHEAAAALQAAADIC+wHsR1BPUwAAAfQAAAf7AAAURoqljoZHU1VCAAAJ8AAAACAAAAAgbJF0j09TLzIAAAoQAAAAWwAAAGB+FsNBY21hcAAACmwAAAGdAAAB+uY47ZljdnQgAAAMDAAAADoAAAA..alotmorecharacters...FDmYlYoTkE8HdsTFF2cwU74AAU/lecUAAA==) format('woff'),
         url('proximanova-bold-webfont-webfont.ttf') format('truetype'),
         url('proximanova-bold-webfont-webfont.svg#ProximaNovaBold') format('svg');
    font-weight: normal;
    font-style: normal;

}

How to get around Internet Explorer 11 ignoring my font-face due to cache-control headers?

As mentioned throughout the post, removing cache-control and pragma headers certainly fixes the issue. However I had certain requirements to keep these headers. While I didn't directly fix this issue, this is how it was resolved for me -

Our application is deployed to an Azure App Service that utilizes Azure Front Door. I believe front door overwrites some of the headers with its own, so when I deployed it to the environment with front door, the issue disappeared altogether.

I should also mention that I did try the <location> and path suggestions, but those did not work for me.

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