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Configuring SSH
Overview
Secure Shell (SSH) is a network security protocol. Using encryption and authentication, SSH can
implement secure remote access and file transfer over an insecure network.
SSH uses the typical client-server model to establish a channel for secure data transfer based on TCP.
SSH includes two versions: SSH1.x and SSH2.0 (hereinafter referred to as SSH1 and SSH2), which are
not compatible. SSH2 is better than SSH1 in performance and security.
The device can work as an SSH server or as an SSH client.
•
When acting as an SSH server, the device provides services for SSH clients and supports the
following SSH versions:
{
For Secure Telnet
(Stelnet), Secure File Transfer Protocol (SFTP), or Secure Copy (SCP)
connections, the device supports SSH2 and SSH1 in non-FIPS mode and SSH2 in FIPS mode.
{
For NETCONF-over-SSH connections, the device supports only SSH2 in both non-FIPS and FIPS
modes.
•
When acting as an SSH client, the device supports only SSH2. It allows users to establish SSH
connections with an SSH server.
The device supports the following SSH applications:
•
Secure Telnet
—Stelnet provides secure and reliable network terminal access services. Through
Stelnet, a user can securely log in to a remote server. Stelnet can protect devices against attacks,
such as IP spoofing and plain text password interception. The device can act as an Stelnet server or
an Stelnet client.
•
SFTP
—Based on SSH2, it uses SSH connections to provide secure file transfer. The device can act as
an SFTP server, allowing a remote user to log in to the SFTP server for secure file management and
transfer. The device can also act as an SFTP client, enabling a user to log in from the device to a
remote device for secure file transfer.
•
SCP
—Based on SSH2, it offers a secure approach to copying files. The device can act as an SCP
server, allowing a user to log in to the device for file upload and download. The device can also act
as an SCP client, enabling a user to log in from the device to a remote device for secure file transfer.
•
NETCONF over SSH
—Based on SSH2, it enables users to securely log in to the device through SSH
and perform NETCONF operations on the device through the NETCONF-over-SSH connections.
The device can act only as a server in NETCONF-over-SSH connections. For more information about
NETCONF, see
Network Management and Monitoring Configuration Guide
.
How SSH works
This section uses SSH2 as an example to list the stages to establish an SSH session. For more information
about these stages, see
SSH Technology White Paper
.
