3Com 4200G 12-Port Configuration Manual page 561

Only one user can access a 3com switch 4200G at a given time when the latter operates as an FTP
server.
Operating as an FTP server, a 3com switch 4200G 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.
To protect unused sockets against attacks, the 3com switch 4200G 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.
Follow these steps to configure connection idle time:
To do...
Enter system view
Configure the connection idle time
for the FTP server
Specifying the source interface and source IP address for an FTP server
You can specify the source interface and source IP address for an FTP server to enhance server
security. After this configuration, FTP clients can access this server only through the IP address of the
specified interface or the specified IP address.
Source interface refers to the existing VLAN interface or Loopback interface on the device. Source IP
address refers to the IP address configured for the interface on the device. Each source interface
corresponds to a source IP address. Therefore, specifying a source interface for the FTP server is the
same as specifying the IP address of this interface as the source IP address.
Follow these steps to specify the source interface and source IP address for an FTP server:
Use the command...
system-view
ftp timeout minutes
1-3
Remarks
—
Optional
30 minutes by default