I am using Build 2000012415 I currently have proxies set to manual. The ftp and http proxy are both set to our corporate firewall proxy. This proxy requires authentication. HTTP is now working since the proxy authentication patch for bug 22405 was applied. FTP does not work at all when my proxy is set to manual- in other words: If I enter the URL ftp://www.mozilla.org/pub/mozilla/nightly/ which should return a directory listing, nothing happens except the message in the status bar says "Beginning FTP transaction." No log messages are displayed in the dos log window, the throbber never throbs, and the screen acts as if I have not even clicked on anything. If, instead of entering a url for an ftp directory listing, I enter a specific URL for a file, such as ftp://ftp.mozilla.org/pub/mozilla/nightly/2000-01-25-17-M14/mozilla-win32.zip I get the exact same response: status="Beginning FTP transaction", no log messages, throbber does nothing, other than status bar message - current window is unchanged. If I click on a link instead of manually entering the URL I still experience the same behavior. NOW - If I change my proxy setting to direct connection to the internet and I try to ftp files from our intranet, the ftp functionality works just fine. Because of this, I suspect that the problem is related to proxy authentication on the ftp channel. I noticed that the changes to fix bug 22405 were applied to the http channel. I suspect that something similar needs to be done for the ftp channel.
see also bug#15594
verified dupe of 15594