1558493 - Can no longer proxy localhost with SOCKS

Status: RESOLVED DUPLICATE of bug 1535581

(Core :: Networking, defect)

Description

[Chris Knowles]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0

Steps to reproduce:

Under Options -> General -> Network Settings, set proxy access to "Manual Proxy Configuration"
Set SOCKS host to localhost, with port 1080, select SOCKS v5
Ensure "No proxy for" field is empty
Click OK
Run local webserver (e.g. on port 8080)

Actual results:

Firefox cannot reach remote website (e.g. mozilla.org), message "The proxy server is refusing connections"
Firefox WILL connect to the local webserver, with address localhost:8080

Expected results:

Firefox cannot reach remote website (e.g. mozilla.org)
Firefox CANNOT to the local webserver, with address localhost:8080

Comment 1

[Chris Knowles]

I believe this bug is relatively new. I have been using this setup, along with a PuTTY SSH tunnel, to access a remote server and hit a webserver listening on localhost there. After failing to get it working yesterday on my main PC, I tested it on an old laptop running (I think) Firefox 66, and it worked fine. This morning that laptop updated itself to 67 when I started Firefox, and it no longer works there, either.