Firefox Community Forum

Hello everyone,

We are currently investigating an issue where browsers are sending HTTP requests with Connection: close in the header during integrated Windows authentication (NTLM authentication) via SAML Service Provider (SP), leading to premature termination of the TCP connection.

This behavior occurs in the middle of the authentication process, preventing the NTLM authentication from completing and subsequently prompting for re-authentication.

We have observed the following browser behaviors:

Chrome and Edge: These browsers function without issues, communicating with Connection: keep-alive. Safari (macOS): Older versions of macOS with Safari exhibit the Connection: close behavior, leading to authentication failure. Newer versions of macOS with Safari work correctly with Connection: keep-alive. Firefox (macOS): Even on the latest versions of macOS, Firefox continues to attach Connection: close, resulting in authentication failure. Upon reviewing logs, we've identified that various browsers attach the Connection: close header during the NTLMSSP_NEGOTIATE request in the NTLM authentication sequence. Although this happens in an environment with a load balancer, we have confirmed that the load balancer is not modifying the header; rather, the client (browser) is adding it.

We would appreciate your insights into the conditions under which Firefox attaches Connection: close to HTTP requests, especially considering the differences across macOS versions and other browsers, addressing the following points:

Are there any known conditions or past cases where Firefox outputs Connection: close in an NTLM authentication environment via SAML SP? Given that older Safari versions show similar behavior, we are also considering if there's a common factor depending on NTLM authentication and browser version. What are the general heuristics, logic, or triggers for a browser to decide to "close" a connection or to attach Connection: close? We are particularly interested in cases that occur mid-authentication process. Could specific configurations (e.g., the combination of SAML and NTLM authentication, or the presence of an intermediate proxy/load balancer) potentially influence Firefox's Connection: close behavior? Are there any additional logs or debugging information we should collect from the Firefox client side to further pinpoint this issue? Any guidance or suggestions you could provide to help us resolve this problem would be greatly appreciated.

Thank you.

While browsing on my desktop , I am unable to open E Shram Card blog. it appears like there is an error in connection , but despite of good connection, cannot open it.

I just started up my new MacBook Pro, M5 pro machine and Firefox will not work. Tahoe 26.3 is OS.

Dale Howard Jonesboro, GA

PS--Safari and DuckDuck Go browsers are working normally.

The connection was reset

The connection to the server was reset while the page was loading.

   The site could be temporarily unavailable or too busy. Try again in a few moments.
   If you are unable to load any pages, check your computer’s network connection.
   If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.

What can I do to resolve this problem.....Problem loading page

I can't access FSIS website which I need to do so for my job. This is what I get

"Firefox can't connect to the server at usda.gov Try connecting with a different device Check your modem or router Disconnect and reconnect to Wi-Fi"

I can't do any of those things because they make absolutely no sense. Nothing is wrong with my router, Wi-Fi. It's your program.

when i enter a web address to enter a search address to find the finformation being sent to me thaty is located at this address; kdrive.informiak.combold textI get the message  ;

Hmm. We’re having trouble finding that site.

We can’t connect to the server at kdrive.informiak.com.

If you entered the right address, you can:

   Try again later
   Check your network connection
   Check that Firefox has permission to access the web (you might be connected but behind a firewall)

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Server Not Found

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Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi.

Bonjour, depuis la mise à jour je ne peux plus me connecter sur mon NAS.

Il semble y avoir un problème sur ce site

Firefox ne peut pas se connecter au serveur à l’adresse .....

Par contre je peux me connecter depuis Safari donc le problème semble venir de Firefox.

Server Not Found

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Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi.

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Server Not Found

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Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi.

Learn more…

Firefox ran all right, i.e. accessed anywhere in the world. But after I specified Express VPN to apply VPN to Firefox, Firefox stopped finding sites as if it lost name resolving ability. When I did a similar thing for Google Chrome or Microsoft Edge, such things did not happen.

I have websites that are blocked on one of my computers and not another. Why? VPN is not on. Server Not Found

Firefox can’t connect to the server at link.mail.beehiiv.com What can you do about it?

Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi.