Comment 7 for bug 308952

User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.6) Gecko/2009020911 Ubuntu/8.04 (hardy) Firefox/3.0.6
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.6) Gecko/2009020911 Ubuntu/8.04 (hardy) Firefox/3.0.6

during the past months various FTP servers have changed their behavior how to shut down encrypted connections. this has been inspired by a change in the filezilla ftp client implementation, see http://forum.filezilla-project.org/viewtopic.php?f=2&t=7688

vsftpd since version 2.0.7 also changed the way tls connections are closed. since then fireftp, a popular ftp addon for firefox, is awfully slow. this has been reported here: https://www.mozdev.org/bugs/show_bug.cgi?id=20043
since fireftp uses the mozilla framework for ssl bugzilla.mozilla.org is the right place to report the bug.

from what i've seen the problem is as follows:
# fireftp opens an encrypted connection
# command channel (e.g. authentication or noop) works fine
# when you do a directory listing or file transfer it opens a new data connection using passive ftp
# the server replies with the requested data on the new conncetion and sends a tls close notify
# fireftp simply acks this and waits for more data
# after 5 minutes the server times out and sends a fin/ack packet
# fireftp closes the connection using fin/ack and finally displays the directory / dowloads the file

this means you have to wait 5 minutes for each directory listing or file transfer!

i'll attach an decrypted wireshark screenshot of the data connection

Reproducible: Always