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.

There are times when i am using Firefox that my PC will randomly disconnect from the internet. Sometimes it will reconnect on its own after I close Firefox. Other times I either have to restart my PC or go into Network & Internet settings and connect to my network. I am still running Window 10, free updates. Does anyone know what is causing this? It does not happen with any other browsers.

Firefox 147.0.4 on macOS 26.3 does not work via SOCKS proxy.

Firefox 147.0.4 on Windows 11 x64 works fine via the same intranet SOCKS proxy, with exactly the same settings.

The advantage of Firefox is its flexibility. It supports its own SOCKS proxy settings, independent of systems-wide ones. Unfortunately, it seems this Firefox feature is broken on macOS (but Windows version works perfectly).

Safari 26.3 (21623.2.7.11.6) and DuckDuckGo 1.177.0 (625) web-browsers that use system-wide macOS SOCKS proxy settings also works fine with this intranet proxy server. So it seems SOCKS proxy server itself is OK, and the problem is confined to Firefox on macOS.

Has anyone seen Firefox 147 on macOS work via SOCKS proxy? Is there a principal difference between how Firefox handles SOCKS proxy on macOS vs. Windows? What might be the best way to address the problem on macOS?

Thanks!

I am using 140 ESR version on linux with Cloudflare's DNS over HTTPS and with DOH active for some reason resolving a domain like d3oklwo3y1bx83.cloudfront.net will resolve to local host IP 127.0.0.1.

I am using firefox about:networking#dnslookuptool to test resolution of the domain d3oklwo3y1bx83.cloudfront.net Both with DOH on and off the resolution remains local host. I tried another browser on the same workstation and I was able to receive a resolution of 13.225.193.203 13.225.193.133 13.225.193.64 13.225.193.58 Why is firefox ESR not able to resolve that domain? What are causes ?

Is is firefox dnslookuptool results.

On a dual-stack network, with Windows tcpip6 ‘disabledcomponents’ parameter set to prefer IPv6, Firefox ignores this setting whenever an endpoint resolves both an IPv4 and a NAT64 address.

While monitoring traffic captured while connecting to sites in Firefox, if the initial DNS request for the site comes back with an IPv6 address only, the connection attempts from client’s IPv6 address to destination IPv6. If DNS answers come back with IPv4 and IPv6, the connection attempts IPv6 to IPv6. If DNS answers come back with IPv4 and a NAT64 address, Firefox doesn’t even attempt to connect to the NAT64 address, it immediately defaults to IPv4. I’ve tried disabling the IPv4 fallback setting which doesn’t change the behavior.

We’re running version 140.8.0esr. Is this behavior intended for Firefox? Is there a way to configure Firefox so it doesn’t ignore NAT64 addresses in dual-stack environments? The only way I found to force this was to completely disable the IPv4 stack on the client system’s NIC.

As of recent I increasingly have issues with accessing websites, those websites previously (yesterday) worked fine on Firefox. Version is 148.0 on Mac 26.3 (Apple M3 Silicon).

Now it has completely stopped working. Only websites using direct IP-address still work, all others fail with "Hmm. We’re having trouble finding that site.". Safari still opens the websites flawlessly.

Nothing has changed on the OS level or application level as no updates have been installed (no need, as everything is up to date). Antivirus is BitDefender with extension for Firefox enabled for already an extended time (year or so).

I tried disabling several dns.resolver settings as mentioned in https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can. No improvement whatsoever.

I quit firefox, removed the cache manually and restarted while starting a new test profile, so completely blank. Issue is still there.

DNS Servers on OS-level are correct.

Version 148 was installed last night evening and as such could be the reason for the failure since it is basically the only thing that changed.

When I opened up Firefox this evening, websites stopped working if "DNS over HTTPS" is set to "Max Protection". In some instances, such as YouTube, the website loads, but it acts like you're offline and tells me to turn on my Wi-Fi even though it's already on and running fine. Weirdly, it seems that setting DNS over HTTPS to Max Protection, loading a website, set DNS over HTTPS to a lower setting, and then reloading the website fixes the issue, but it'd still be nice if we didn't have to go through the hassle at all. Thank you for your time and patience.

Sincerely, Watching Forests

all the sights I've used for years will not open and will not work I can't even use them any more they work fine in other browsers don't know what you did but it is almost unusable

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 get a message that says I must log into this network before I can access the internet then I get another message that says the page isn't direct redirecting properly Firefox has detected that the server is redirecting the request for this address in a way that will never be complete the problem can sometimes be solved back calls by disabling or refusing to accept cookies. I have done neither. don't understand what happened I was browsing and all of the sudden I'm not I guess I may have to switch my browser?

bold text When I try to go to my "FIREFOX" it answers me in French of course but here you don't accept to write me in French and so it's very difficult for me ... (could you help me for this of course ???) : "hmm this adress doesn' seem to be valid." Hum, cette adresse ne semble pas valide.

What must I do please ??? [edited from public] @orange.fr

Hi. I have a Dell Inspiron, it’s a few years old, and my computer is running windows. Today I was on a website, doing my assignments as usual when randomly the internet stopped working on the browser (I was on the web for about an hour before this). There was no change to my behavior, I had been on the same site for the whole hour, and had been interacting with the site during that time. My computer still says it’s connected to the internet, and I was even able to play an online game on my computer that I had downloaded, so it looks like my computer is connected to the internet. I’ve tried to clear my cache and open private windows but that didn’t help.

After the most recent upgrades (both MacOS to 26.4 beta and Firefox 147.0.4), Firefox is giving me this message: Hmm. We’re having trouble finding that site. Any suggestions?

i want to access www.fintreeindia.com i pursue professional courses that's my class website and also i could not access youtube also my exam are nearly