HTTP is broken in IE11 Mobile

RFC2616 states:

A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP URL)


  • a request to must give a header of "Host:" or "Host:"
  • a request to must give a header of "Host:"

On the latest developer preview, IE11 Mobile does not correctly handle the second case. This can be verified with a tiny python server:

from bottle import *


    return repr(request.headers.items())

run(host='', port=8080)

Is this bug known about?


Hello Eric:

Thank you for posting to the forum regarding the issues you are having with the web browser on your Windows Phone running the 8.1 developer preview.  I see that you found an issue with how certain sites are handled on the browser.  At this point I have a couple questions and one suggestion.

My main question is what is happening when you attempt to connect via port 8080?  I see you mention it does not handle it correctly but I am unable to determine how it is being handled based on the information provided.  If you could provide as much detail as possible that would be greatly appreciated.

My next question is, was this something that did not happen when accessing the site via the browser before you installed the developer preview?  If this did work as expected then any additional information related to your experience on the phone then would be appreciated.

For the time being I would suggest you post your feedback/suggestions regarding this to the following forum, .  This forum is used to develop updates for existing products and in the development of new products.  Posting here will further ensure your concerns are seen and addressed.

Please let us know if you have any other questions or concerns.

Mark W.

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Question Info

Last updated April 14, 2021 Views 109 Applies to: