User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:22.214.171.124) Gecko/20080829 Firefox/126.96.36.199 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:188.8.131.52) Gecko/20080829 Firefox/184.108.40.206 The SOCKS5 specification (RFC 1928) says the following: Compliant implementations MUST support GSSAPI and SHOULD support USERNAME/PASSWORD authentication methods. Yet firefox has no basic support for the SOCKS5 username/password auth method, as you would expect. This auth method is a very simple concept to impliment as per RFC 1929. The SOCKS5 specification (RFC 1928) says the following: If the selected METHOD is X'FF', none of the methods listed by the client are acceptable, and the client MUST close the connection. If this is the case, firefox displays a blank page, instead of an error as you would expect. Having no error makes debugging far more difficult that is required. This causes users to produce the "not working" statement, instead of reporting an error. Reproducible: Always Steps to Reproduce: 1. Use a SOCKS5 server that uses USERNAME/PASSWORD authentication method. 2. Try and make it work with firefox. 3. ??? 4. Profit Actual Results: There's nowhere to put the username and password/a blank page is displayed. Expected Results: Somewhere to put the username and password/display an error.