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Downgrade from HTTP/2 to HTTP 1.1 on specific page RRS feed

  • Question

  • User-41882152 posted

    Is it possible to downgrade from HTTP/2 to HTTP 1.1 in IIS 10 on specific ASP Classic page?
    Unfortunately Response.Flush doesn't work with H2. I need it in some pages in witch I show progress of long time processes.

    I try to move this pages from HTTP to HTTPS using URLRewrite. But this is a bad idea because HSTS browsers politics.

    May be it's possible by adding some headers to the response?

    Monday, March 2, 2020 10:47 AM

All replies

  • User-2064283741 posted
    You can only degrade for the whole server. Not a site or page.
    Here in the answer is how to do it.

    https://stackoverflow.com/questions/44660634/how-to-disable-http-2-on-iis-of-windows-server-2016
    Monday, March 2, 2020 1:14 PM
  • User-460007017 posted

    Hi Andrey.IIS,

    I think it is impossible to enable https/1.1 for specific page because application and your registry key decide which protocol should be used.

    However, in some case, HTTP/2 is not supported and it will force IIS fail back to HTTP/1.1 maybe you could try that workaround.

    https://docs.microsoft.com/en-us/iis/get-started/whats-new-in-iis-10/http2-on-iis

    If the reply is helpful, it is appreciated if you could mark it as answer.

    Best Regards,

    Jokies Ding

    Tuesday, March 3, 2020 3:30 AM
  • User-41882152 posted

    Hi Jokies,

    In link than you provided: "server sending an error code to the client instructing it to retry over an HTTP/1.1 connection". But how I can do it in practic in ASP Classic page? Wich error do I need to send to a client initiating a HTTP 2 connection for them to downgrade the connection to HTTP/1.1?

    Sunday, March 15, 2020 7:19 PM
  • User-2064283741 posted
    AFIAC these commands are all at a level before they get to IIS. This is on the network communication in the HTTP.SYS and that is before the traffic even gets to IIS.
    There is nothing you can do about it apart from having a dedicated machine for just http 1.1 communication
    Sunday, March 15, 2020 8:17 PM