HTTP 502 Proxy Error - The login request was denied
Symptom: When accessing an external FTP site that requires authentication, the following error is received: "HTTP 502 Proxy Error - The login request was denied."
Issue: Web proxy normally sends anonymous authentication information to an FTP site in the first request. If the FTP site rejects and closes the connection at the first try, this error is issued. If you monitor the FTP traffic, you will see a log entry similar to: "Port: 21 FTP failed connection attempt user: anonymous request: Get ftp://FTPServer/."
Solution: When accessing an external FTP site that requires authentication from a Web proxy client, provide credentials in the URL, in the following format: ftp://username:password@FTPServerName.
This issue does not occur in the following circumstances:
- SecureNAT clients or Firewall clients make the FTP request.
- The Enable folder view for FTP sites check box is selected in Internet Explorer. With this setting enabled, Internet Explorer sends the request directly to the FTP site if it can resolve the remote host name, ignoring browser settings. If the host name cannot be resolved, the browser is used.
