How to Band-aid Fix Intermittent Firefox Proxy Failures for VLAN

by Rian

Before I get into details, if I have to fathom a guess based on what I’ve read so far, this is likely a bug on Firefox’s part. I’m not up to date with Firefox development and the priority lists they must have; but reading some of the other proxy plugins GitHub gave some ideas as to what could be the potential problems. I’ll add more details as I find more about it.

Symptoms

The issue at hand is relatively simple. The same proxy settings that used to work on all machines somehow sporadically fails on one machine. At first I assumed my tinkering with Pi VPN routers must be the issue, but soon I realized Firefox running on another Mac is still connected to the Socks5 server via Firefox. Same settings, same server, something was off.

Clean installing Firefox did not solve the problem. In fact, I was more frustrated to find out that the problem wasn’t persistent. With nothing’s changed, I was able to browse on Firefox via proxy.

Band-aid Fix

If the proxy server in question is yours, you are in luck. Frankly, this is a temporary patch work to a problem that requires more attention. If you were following my how-to post on building VLAN, you would have a Raspberry Pi or equivalent mini-PC running as a VLAN router, possibly running either Dante for SOCKS, or Privoxy for HTTP proxy. The band-aid is simple: use HTTP for the time being.

At the risk of sounding cynical, plugin developers have apparently touched on the similar subject before. Firefox has had issues with SOCKS proxy before, and the thread I’ve read was dated only back in December 2023. Considering the proxy server was functional, and other browsers —including Firefox on a different machine, no less— was able to reach it, I am inclined to believe what was said about how Firefox is handling SOCKS proxy. Again, switching the protocol over to HTTP simply solves the issue.

At the end of the day, the choice of which protocols to use lies in the hand of the network manager. If this is home or small office environment, it’s less complicated to add HTTP service to existing setup —that’s what I did. Whereas in anything bigger, I can only imagine the trouble the user will go through. As I am writing this, Firefox is working again with SOCKS proxy. For the life of me, I hate it when the bugs ‘disappear’.