1.1 Introduction
to FTP and SFTP
FTP (file transfer protocol) is commonly
used in IP-based networks to transmit files. Before World Wide Web comes into
being, files are transferred through command lines, and the most popular
application is FTP. At present, although E-mail and Web are the usual methods
for file transmission, FTP still has its strongholds.
As an application layer protocol, FTP is
used for file transfer between remote server and local client. FTP uses TCP
ports 20 and 21 for data transfer and control command transfer respectively. Basic
FTP operations are described in RFC 959.
FTP-based file transmission is performed in
the following two modes:
l
Binary mode for program file transfer
l
ASCII mode for text file transfer
An H3C S3100 series Ethernet switch can act
as an FTP client or the FTP server in FTP-employed data transmission:
Table 1-1
Roles that an H3C S3100 series Ethernet switch acts
as in FTP
|
Item
|
Description
|
Remarks
|
|
FTP server
|
An
Ethernet switch can operate as an FTP server to provide file transmission
services for FTP clients. You can log in to a switch operating as an FTP
server by running an FTP client program on your PC to access files on the FTP
server.
|
The prerequisite is that a route exists
between the switch and the PC.
|
|
FTP client
|
In this
case, you need to establish a connection between your PC and the switch
through a terminal emulation program or Telnet, execute the ftp X.X.X.X
command on your PC. (X.X.X.X is the IP address of an FTP server or a host
name), and enter your user name and password in turn. A switch can operate as
an FTP client, through which you can access files on the FTP server.
|
Secure FTP (SFTP) is established based on
an SSH2 connection. It allows a remote user to log in to a switch to manage and
transmit files, providing a securer guarantee for data transmission. In
addition, since the switch can be used as a client, you can log in to remote
devices to transfer files securely.
Table 1-2
FTP configuration tasks
Configure the user
name and password for the FTP user and set the service type to FTP. To use FTP
services, a user must provide a user name and password for being authenticated
by the FTP server. Only users that pass the authentication have access to the
FTP server.
Table 1-3
Create an FTP user
|
Operation
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
Add a local user and enter local user
view
|
local-user user-name
|
Required
By default, no local user is configured.
|
|
Configure a password for the specified
user
|
password {
simple | cipher } password
|
Optional
By default, no password is configured.
|
|
Configure the service type as FTP
|
service-type ftp
|
Required
By default, no service is configured.
|
Table 1-4 Enable
an FTP server
|
Operation
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
Enable the FTP server function
|
ftp server enable
|
Required
Disabled by default.
|
l
Only one user can access an H3C S3100 series Ethernet
switch at a given time when the latter operates as an FTP server.
l
Operating as an FTP server, an H3C S3100 series Ethernet
switch 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.
l
You cannot access an H3C S3100 series switch
operating as an FTP server through Microsoft Internet Explorer. To do so, use
other client software.
To protect unused
sockets against attacks, the S3100 Ethernet switch provides the following
functions:
l
TCP 21 is enabled only when you start the FTP
server.
l
TCP 21 is disabled when you shut down the FTP
server.
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
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
Configure the connection idle time for
the FTP server
|
ftp timeout
minutes
|
Optional
30 minutes by default
|
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
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
On the FTP server, disconnect a specified
user from the FTP server
|
ftp
disconnect user-name
|
Required
|
With an H3C S3100
series Ethernet switch acting as the FTP server, if a network administrator
attempts to disconnect a user that is uploading/downloading data to/from the
FTP server the S3100 Ethernet switch will disconnect the user after the data
transmission is completed.
Displaying a banner: With a banner
configured on the FTP server, when you access the FTP server through FTP, the
configured banner is displayed on the FTP client. Banner falls into the
following two types:
l
Login banner: After the connection between an
FTP client and an FTP server is established, the FTP server outputs the
configured login banner to the FTP client terminal.
Figure 1-1 Process of displaying a login
banner
l
Shell banner: After the connection between an
FTP client and an FTP server is established and correct user name and password
are provided, the FTP server outputs the configured shell banner to the FTP
client terminal.
Figure 1-2 Process of displaying a shell
banner
Table 1-7
Configure the banner display for an FTP server
|
Operation
|
Command
|
Description
|
|
Enter
system view
|
system-view
|
—
|
|
Configure
a login banner
|
header
login text
|
Required
Use either
command or both.
By
default, no banner is configured.
|
|
Configure
a shell banner
|
header
shell text
|
For details about
the header command, refer to the Login part of the manual.
After the above
configurations, you can execute the display commands in any view to display
the running status of the FTP server and verify your configurations.
Table 1-8 Display FTP server information
|
Operation
|
Command
|
Description
|
|
Display
the information about FTP server configurations on a switch
|
display
ftp-server
|
Available
in any view
|
|
Display
the login FTP client on an FTP server
|
display
ftp-user
|
By default a switch can operate as an FTP
client In this case you can connect the switch to the FTP server to perform
FTP-related operations (such as creating/removing a directory) by executing
commands on the switch. Table
1-9 lists the operations that can be performed on
an FTP client.
Table 1-9 Basic configurations on an FTP
client
|
Operation
|
Command
|
Description
|
|
Enter FTP client view
|
ftp [ cluster | remote-server [ port-number
] ]
|
—
|
|
Specify to transfer files in ASCII
characters
|
ascii
|
Use either command
By default, files are transferred in
ASCII characters.
|
|
Specify to transfer files in binary
streams
|
binary
|
|
Set the data transfer mode to passive
|
passive
|
Optional
passive by
default.
|
|
Change the working directory on the
remote FTP server
|
cd pathname
|
Optional
|
|
Change the working directory to be the
parent directory
|
cdup
|
|
Get the local working path on the FTP
client
|
lcd
|
|
Display the working directory on the FTP
server
|
pwd
|
|
Create a directory on the remote FTP
server
|
mkdir pathname
|
|
Remove a directory on the remote FTP
server
|
rmdir pathname
|
|
Delete a specified file
|
delete remotefile
|
|
Query a
specified file on the FTP server
|
dir [
remotefile ] [ localfile ]
|
Optional
If no file
name is specified, all the files in the current directory are displayed.
The
difference between these two commands is that the dir command can
display the file name, directory as well as file attributes; while the Is
command can display only the file name and directory.
|
|
ls [ remotefile ] [ localfile ]
|
|
Download a
remote file from the FTP server
|
get remotefile
[ localfile ]
|
Optional
|
|
Upload a
local file to the remote FTP server
|
put localfile
[ remotefile ]
|
|
Rename a
file on the remote server
|
rename remote-source
remote-dest
|
|
Log in
with the specified user name and password
|
user username
[ password ]
|
|
Connect to
a remote FTP server
|
open { ip-address | server-name
} [ port ]
|
|
Terminate
the current FTP connection without exiting FTP client view
|
disconnect
|
|
close
|
|
Terminate
the current FTP connection and return to user view
|
quit
|
|
bye
|
|
Display
the online help about a specified command concerning FTP
|
remotehelp [ protocol-command
]
|
|
Enable the verbose function
|
verbose
|
Optional
Enabled by default
|
I. Network requirements
A switch operates as an FTP server and a remote
PC as an FTP client. The application switch.bin of the switch is stored
on the PC. Upload the application to the remote switch through FTP and use the boot
boot-loader command to specify switch.bin as the application for
next startup. Reboot the switch to upgrade the switch application and download
the configuration file config.cfg from the switch, thus to back up the
configuration file.
l
Create a user account on the FTP server with the
user name “switch” and password “hello”.
l
The IP addresses 1.1.1.1 for a VLAN interface on
the switch and 2.2.2.2 for the PC have been configured. Ensure that a route exists
between the switch and the PC.
II. Network diagram
Figure
1-3 Network diagram for FTP configurations: a
switch operating as an FTP server
III. Configuration procedure
1)
Configure Switch A (the FTP server)
# Log in to the switch and enable the FTP
server function on the switch. Configure the user name and password used to
access FTP services, and specify the service type as FTP (You can log in to a
switch through the Console port or by telnetting the switch. See the “Login”
module for detailed information.)
# Configure the FTP user name as “switch”,
the password as “hello”, and the service type as FTP.
<Sysname>
<Sysname> system-view
[Sysname] ftp server enable
[Sysname] local-user switch
[Sysname-luser-switch] password
simple hello
[Sysname-luser-switch] service-type
ftp
2)
Configure the PC (FTP client)
Run an FTP client application on the PC to
connect to the FTP server. Upload the application named switch.bin to
the root directory of the Flash memory of the FTP server, and download the
configuration file named config.cfg from the FTP server. The following
takes the command line window tool provided by Windows as an example:
# Enter the command line window and switch
to the directory where the file switch.bin is located. In this example
it is in the root directory of C:\.
C:\>
# Access the Ethernet switch through FTP.
Input the user name “switch” and password “hello” to
log in and enter FTP view.
C:\> ftp 1.1.1.1
Connected to 1.1.1.1.
220 FTP service ready.
User (1.1.1.1:(none)): switch
331 Password required for switch.
Password:
230 User logged in.
ftp>
# Upload the switch.bin file.
ftp> put switch.bin
200 Port command okay.
150 Opening ASCII mode data
connection for switch.bin.
226 Transfer complete.
ftp: 75980 bytes received in 5.55
seconds 13.70Kbytes/sec.
# Download the config.cfg file.
ftp> get config.cfg
200 Port command okay.
150 Opening ASCII mode data
connection for config.cfg.
226 Transfer complete.
ftp: 3980 bytes received in 8.277
seconds 0.48Kbytes/sec.
This example uses the command line window
tool provided by Windows. When you log in to the FTP server through another FTP
client, refer to the corresponding instructions for operation description.
Caution:
l
If available space on the Flash memory of the
switch is not enough to hold the file to be uploaded, you need to delete files not
in use from the Flash memory to make room for the file, and then upload the
file again. The files in use cannot be deleted. If you have to delete the files
in use to make room for the file to be uploaded, you can only delete/download them
through the Boot ROM menu.
l
H3C series switch is not shipped with FTP client
application software. You need to purchase and install it by yourself.
3)
Configure Switch A (FTP server)
# After uploading the application, use the boot
boot-loader command to specify the uploaded file (switch.bin) to be
the startup file used when the switch starts the next time, and restart the
switch. Thus the switch application is upgraded.
<Sysname> boot boot-loader switch.bin
<Sysname> reboot
For information about the boot boot-loader command and how to
specify the startup file for a switch, refer to the System Maintenance and
Debugging part of this manual.
I. Network requirements
Configure the Ethernet switch as an FTP
server and the remote PC as an FTP client. After a connection between the FTP
client and the FTP server is established and login succeeds, the banner is
displayed on the FTP client.
l
An FTP user named “switch” and the
password “hello” have been configured on the FTP server.
l
The IP addresses 1.1.1.1 for a VLAN interface
on the switch and 2.2.2.2 for the PC have been configured. Ensure that a route exists
between the switch and the PC.
l
Configure the login banner of the switch as
“login banner appears” and the shell banner as “shell banner
appears”.
II. Network diagram
Figure
1-4 Network diagram for FTP banner display configuration
III. Configuration procedure
1)
Configure the switch (FTP server)
# Configure the login banner of the switch
as “login banner appears” and the shell banner as “shell
banner appears”. For detailed configuration of other network
requirements, see section 1.2.3
Configuration Example: A Switch Operating as an FTP
Server.
<Sysname> system-view
[Sysname] header login %login banner
appears%
[Sysname] header shell %shell banner
appears%
2)
Configure the PC (FTP client)
# Access the Ethernet switch through FTP.
Enter the user name “switch“ and the password “hello”
to log in to the switch, and then enter FTP view. Login banner appears after
FTP connection is established. Shell banner appears after the user passes the authentication.
C:\> ftp 1.1.1.1
Connected to 1.1.1.1.
220-login banner appears
220 FTP service ready.
User (1.1.1.1:(none)): switch
331 Password required for switch.
Password:
230-shell banner appears
230 User logged in.
ftp>
I. Network requirements
A switch operates as an FTP client and a
remote PC as an FTP server. The switch application named switch.bin is
stored on the PC. Download it to the switch through FTP and use the boot
boot-loader command to specify switch.bin as the application for
next startup. Reboot the switch to upgrade the switch application, and then upload
the switch configuration file named config.cfg to the “switch”
directory of the PC to back up the configuration file.
l
Create a user account on the FTP server with the
user name “switch” and password “hello”, and grant the
user “switch” read and write permissions for the directory named “Switch”
on the PC.
l
Configure the IP address 1.1.1.1 for a VLAN
interface on the switch, and 2.2.2.2 for the PC. Ensure a route exists between
the switch and the PC.
II. Network diagram
Figure 1-5 Network diagram for FTP
configurations: a switch operating as an FTP client
III. Configuration procedure
1)
Configure the PC (FTP server)
Perform FTP server–related
configurations on the PC, that is, create a user account on the FTP server with
user name “switch” and password “hello”. (For detailed
configuration, refer to the configuration instruction relevant to the FTP server
software.)
2)
Configure the switch (FTP client)
# Log in to the switch. (You can log in to
a switch through the Console port or by telnetting the switch. See the “Login”
module for detailed information.)
Caution:
If available space
on the Flash memory of the switch is not enough to hold the file to be
uploaded, you need to delete files not in use from the Flash memory to make
room for the file, and then upload the file again. The files in use cannot be
deleted. If you have to delete the files in use to make room for the file to be
uploaded, you can only delete/download them through the Boot ROM menu.
# Connect to the FTP server using the ftp
command in user view. You need to provide the IP address of the FTP server,
the user name and the password as well to enter FTP view.
<Sysname> ftp 2.2.2.2
Trying ...
Press CTRL+K to abort
Connected.
220 FTP service ready.
User(none):switch
331 Password required for switch.
Password:
230 User logged in.
[ftp]
# Enter the authorized directory on the FTP
server.
[ftp] cd switch
# Execute the put command to upload the
configuration file named config.cfg to the FTP server.
[ftp] put config.cfg
# Execute the get command to download
the file named switch.bin to the Flash memory of the switch.
[ftp] get switch.bin
# Execute the quit command to terminate
the FTP connection and return to user view.
[ftp] quit
<Sysname>
# After downloading the file, use the boot
boot-loader command to specify the downloaded file (switch.bin) to be
the application for next startup, and then restart the switch. Thus the switch
application is upgraded.
<Sysname> boot boot-loader switch.bin
<Sysname> reboot
For information
about the boot boot-loader command and how to specify the startup file
for a switch, refer to the “System Maintenance and Debugging”
module of this manual.
1.3 SFTP Configuration
Table
1-10 SFTP configuration tasks
Before enabling an
SFTP server, you need to enable the SSH server function and specify the service
type of the SSH user as SFTP or all. For details, see the SSH
server configuration part of SSH Operation Manual of this manual.
Table
1-11 Enable an SFTP server
|
Operation
|
Command
|
Description
|
|
Enter
system view
|
system-view
|
—
|
|
Enable an
SFTP server
|
sftp
server enable
|
Required
Disabled
by default
|
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
1-12 Configure connection idle time
|
Operation
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
Configure the connection idle time for
the SFTP server
|
