Pure-FTPD strange behavior
 

Has pure-ftpd installed in Debian. Created a dummy virtual user for testing.
Configure it to use SSL/TLS and change the listening port. But still can connect by client by using port 21 without SSL/TLS.
Then I stop the pure-ftpd service. Client side can still connect !? Incredible !

I found that the pure-ftpd service can't stop by run "sudo service pure-ftpd stop".
Because I started the service by "sudo /usr/sbin/pure-ftpd -j -lpuredb:/etc/pure-ftpd/pureftpd.pdb &"
I have to kill the process in order to stop it. Ridiculous.
After kill and start the service again, SSL/TLS and the custom port are still NOT WORK