Setting the KeepAlive property to a value of true specifies
that a background worker thread will be created to monitor the
command channel and periodically send NOOP commands to the server if
no commands have been sent recently. This can prevent the server from
terminating the client connection during idle periods where no
commands are being issued. However, it is important to keep in mind
that many servers can be configured to also limit the total amount of
time a client can be connected to the server, as well as the amount
of time permitted between file transfers. If the server does not
respond to the NOOP command, this option will be automatically
disabled for the remainder of the client session.
It is recommended that you only enable this option if the
connection to the server must be maintained for a relatively long
period of time where there will be periods of inactivity. Never make
the assumption that this option can prevent the server from
terminating the connection. Most sites, particularly public FTP
servers accessed over the Internet, have fairly restrictive policies
designed to prevent clients from maintaining long-term connections.
In most cases, if there are periods of time where your application
will not be transferring files, it is more appropriate to disconnect
from the server and then reconnect at a later point rather than
attempting to hold the connection open.
The default value for this property is false.