HPE FlexFabric 5940 SERIES, Руководство по настройке безопасности

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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 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.
•
Secure File Transfer Protocol —Based on SSH2, SFTP 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.
•
Secure Copy —Based on SSH2, SCP offers a secure method to copy 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 NETCONF-over-SSH server.
For more information about NETCONF, see
Network Management and Monitoring
Configuration Guide .
When acting as an SSH client or server, the device supports the following SSH versions:
•
When acting as an SSH client, the device supports only SSH2.
•
When acting as an Stelnet, SFTP, or SCP server, the device supports both SSH2 and SSH1 in
non-FIPS mode and only SSH2 in FIPS mode.
•
When acting as a NETCONF-over-SSH server, the device supports only SSH2.
How SSH works
This section uses SSH2 as an example to describe the stages to establish an SSH session. For
more information about these stages, see
SSH Technology White Paper .
Table 22 Stages to establish an SSH session
Stages Description
Connection establishment
The SSH server listens to connection requests on port 22. After a client
initiates a connection request, the server and the client establish a
TCP connection.
Version negotiation The two parties determine a version to use.
Algorithm negotiation
SSH supports multiple algorithms. Based on the local algorithms, the
two parties negotiate the following algorithms: