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ajdonik
ajdonik
New Member
July 31, 2025
Solved

Fortiweb : SSE (servent sent event) [Accept: text/event-stream] KO when HTTP2 enabled

  • July 31, 2025
  • 4 replies
  • 1185 views

Hi,

 

I am running an SPA (JS) application behind fortiweb in monitor mode.

When HTTP2 is activated, the https (http2) request keeps infinitely pending.

This request has the header "text/event-stream"

 

When bypassing fortiweb and accessing directly apache in HTTPS (HTTP2), everything is fine.

Could it be that fortiweb (7.6.4) has some issue heandling SSE requests ?

Thank you for your help

 

Regards

Thibaut

Best answer by abelio

Hello Thibaut

If your deploy mode is content routing , you should  disable HTTP/2 in the server pool config
(and enabled in the server policy)

Explanation is: even clients use HTTP/2 , the traffic Fortiweb<->server web must be HTTP; because of that you disable http/2 in the server pool

hope it helps

4 replies

abelio
SuperUser
abelio
SuperUser
August 2, 2025

Hello Thibaut

 

Let assume you're running your fweb in Reverse Proxy. 
If deployment mode is Single Server/Server Balance: did you enable HTTP/2 in the server policy AND in relevant server pool ?

Otherwise, If the Deployment Mode in your server policy conf is
HTTP Content Routing and you enabled HTTP/2 , verify your server pool and disable HTTP/2 (because traffic between fweb and backend server must be HTTP)

These were settings for 7.4x, I guess  that there' re not changes in  7.6.4 for http/2.


Hope it helps

 

 

ajdonik
ajdonikAuthor
New Member
August 4, 2025

Hello Abelio,

 

Thank you for your reply.

Deployment mode is HTTP Content Routing.

I have tried several combinations :

  • Server pool HTTP/2 on and Server policy HTTP/2 on -> impossible to connect (0 byte response)
  • Server pool HTTP/2 Off and Server policy HTTP/2 on -> Works fine
  • Server pool HTTP/2 On and Server Policy HTTP/2 Off -> applications loads until request with header "text/event-stream" is sent, then pending status on this request in my browser (tested with several browsers also in private mode).
  • Server pool HTTP/2 Off and Server policy HTTP/2 off -> Works fine

Here is 2 screenshots from the last (working) configuration :

 

server policy http2 offserver policy http2 offserver pool http2 offserver pool http2 off

So far, i have a workaround (disabling HTTP2), but for better performances it would be better to have it working in HTTP2.

 

Kind Regards

 

Thibaut

abelio
SuperUser
abelioAnswer
SuperUser
August 4, 2025

Hello Thibaut

If your deploy mode is content routing , you should  disable HTTP/2 in the server pool config
(and enabled in the server policy)

Explanation is: even clients use HTTP/2 , the traffic Fortiweb<->server web must be HTTP; because of that you disable http/2 in the server pool

hope it helps

    ajdonik
    ajdonikAuthor
    New Member
    August 5, 2025

    Hello,

    Sorry I moved to fast the topic status to "solved".

    As soon as i turn HTTP2 on in server policy, the browser keeps pending on "text/event-stream" request.

    Whatever the value of HTTP2 in server pool.

    Only disabling HTTP2 (between browser and fortiweb) works.

    Kind regards

     

    Thibaut

      abelio
      SuperUser
      abelio
      SuperUser
      August 6, 2025

      Hello Thibaut

      I'm sorry this issue continues;  I´d suggest to open a TAC ticket in order to troubleshoot your specific scenario
      No problem with the 'solved'status you made, I guess that it can be removed, or moderator could do that

      best regards

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