3Com 4210 9-Port Configuration Manual page 636

Only one user can access a Switch 4210 at a given time when the latter operates as an FTP server.
Operating as an FTP server, a Switch 4210 cannot receive a file whose size exceeds its storage
space. The clients that attempt to upload such a file will be disconnected with the FTP server due to
lack of storage space on the FTP server.
You cannot access a Switch 4210 operating as an FTP server through Microsoft Internet Explorer.
To do so, use other client software.
To protect unused sockets against attacks, the Switch 4210 provides the following functions:
TCP 21 is enabled only when you start the FTP server.
TCP 21 is disabled when you shut down the FTP server.
Configuring connection idle time
After the idle time is configured, if the server does not receive service requests from a client within a
specified time period, it terminates the connection with the client, thus preventing a user from occupying
the connection for a long time without performing any operation.
Table 1-5 Configure connection idle time
Operation
Enter system view
Configure the connection idle
time for the FTP server
Disconnecting a specified user
On the FTP server, you can disconnect a specified user from the FTP server to secure the network.
Table 1-6 Disconnect a specified user
Operation
Enter system view
On the FTP server, disconnect a specified
user from the FTP server
Command
system-view
ftp timeout minutes
Command
system-view
ftp disconnect user-name
1-3
Description
—
Optional
30 minutes by default
Description
—
Required