Chapter 1 Ssh Terminal Service Configuration; Ssh Terminal Services; Introduction To Ssh - H3C S7500 Series Operation Manual

Operation Manual – SSH Terminal Service
H3C S7500 Series Ethernet Switches

Chapter 1 SSH Terminal Service Configuration

1.1 SSH Terminal Services

This section covers these topics:

Introduction to SSH

Configuring an SSH Server
Configuring an SSH Client
Displaying SSH Configuration
SSH Server Configuration Example
SSH Client Configuration Example
1.1.1 Introduction to SSH
Secure shell (SSH) can provide information security and powerful authentication to
prevent such assaults as IP address spoofing, plain-text password interception when
users log on to the Switch remotely in an insecure network environment.
As an SSH server, a switch can connect to multiple SSH clients; as an SSH client, a
switch can establish SSH connections with switches or UNIX hosts that support SSH
server.
Currently, the S7500 series switches support SSH2.0 (compatible with SSH1.5).
The communication process between the server and client includes the following five
stages:
1) Version negotiation stage. The following operations are completed at this stage:
The client sends TCP connection requests to the server.
When a TCP connection is established, both ends begin to negotiate the SSH
version.
If they can work together in harmony, they enter the key algorithm negotiation
stage. Otherwise the server removes the TCP connection.
2) Key and algorithm negotiation stage. The following operations are completed at
this stage:
The server and the client send key algorithm negotiation packets to each other,
which include the supported server-side public key algorithm list, encryption
algorithm list, MAC algorithm list, and compression algorithm list.
Based on the received algorithm negotiation packets, the server and the client
figure out the algorithms to be used.
The server and the client use the DH key exchange algorithm and parameters
such as the host key pair to generate the session key and session ID.
Chapter 1 SSH Terminal Service Configuration
1-1