I use Windows for work and Firefox was having issues with DNS resolution. I reached out to my IT and they couldn’t figure it out. Chrome was also failing to resolve the IP: timing out/errors with connection status.
But Microsoft Edge was totally fine. It resolved websites without an issue. I told IT about this, but they said they haven’t implemented any policies that would hurt Firefox or Chrome. I found some forums online where people suggested renaming the Firefox.exe to something else; I renamed the executable to Fox.exe and suddenly it worked - immediately. I tried A/B testing this. I renamed it back to Firefox.exe and it failed again. Renamed it to Fox.exe and it worked.
What the hell is this? Someone said it was Microsoft Defender, but my IT didn’t seem to think so and I trust them. They would have just said “don’t use Firefox” if they didn’t want me using it. They spent quite a bit of time reading logs and such to help me debug this.
I don’t understand how something like this can pass under Window’s radar. Bizarre behavior that seemed to impact any non-Edge browser. Super sketchy.
For now, I run Fox.exe. But this does cause issues. Windows - in all of its genius - doesn’t recognize Fox.exe as a browser. I can’t set it as a default browser for my OS. That means the OS fails on all hyperlinks since it doesn’t have a default browser to open them. Slack, Outlook, etc. They all fail. So now I’m left copy/pasting links into my browser URL bar if I need them.
I hate Windows. /rant
Sounds like a firewall issue. No idea why something or somebody would block your browsers. But check incoming and outgoing rules under “Windows Defender Firewall with Advanced Security”, Firefox should be multiple times on the incoming list, but not the outgoing.
I checked those first (and just re-checked them) and I didn’t find any issues with the firewall. Firefox is listed multiple times - explicitly pointing towards the correct executable - in the incoming list, but not the outgoing.
Alright. Hmm… You could be extra sure by disabling the firewall entirely and see if this stops happening. Shouldnt be anything else in Windows that blocks executables. Any 3rd party antivirus, btw?
Could also be that something is blocking DNS that isnt https. I see Edge got secure dns enabled by default. In Firefox it says “off” for me, which the documentation says means “On in available regions”.
Or you could try setting a manual dns in the browser, to either 1.1.1.1 (cloudflare) or 8.8.8.8 (google) and see if that does anything.
Other than that, idk.
I’ve tried removing the firewall but my IT controls it and they probably don’t want it to be removed lol
No 3rd party antivirus. Just windows firewall managed in-house. I’ve also changed the DNS over HTTPS as well. I’ve tried flipping that a million times since it’s the most common reason for this issue.
I’ve tried manually setting the DNS in the browser and in my wifi and Ethernet adapters.
It’s crazy.
Whoever suggested you rename the executable is a @#^%ing psychopath. That’s the single dumbest suggestion I’ve ever heard of anyone, anywhere, ever, suggesting in my entire life- so if they had you do anything else, I’d suggest rolling those changes back, uninstalling and reinstalling Firefox.
THEN open Firefox’s settings and check what “DNS over HTTPS” and “Enable secure DNS using:” settings.
I have already tried all of those settings. I debugged everything in the network settings on Firefox and my OS for hours and hours prior to finding the forum with renaming the executable.
Secondly, it was highly effective? So I don’t think they are crazy. Thirdly, naming an executable is not a big deal. I’m a software engineer and it’s not a big deal to change a filename. I don’t know why you reacted so intensely. But I can assure you I’ve tried every network setting I could find. I manually changed the DNS in my network adapter. I changed Firefox’s DNS over HTTP. I tried various proxy settings. I tested all of this over a VPN and without a VPN. I found several possible settings in the about:config settings for Firefox which made no difference.
The only thing that worked was renaming the executable and - like I said - A/B testing it was consistent. It seems like Windows is doing some sort of check to prevent it from doing certain network operations.
