install ssh on debian

在这篇博客文章中，我们将深入探讨如何在Debian系统中安装SSH服务，以提升系统及数据的安全性。SSH（Secure Shell）是一种加密通信协议，其特点是无需直接连接到远程服务器即可进行安全登录和数据传输。在Debian系统中，安装SSH服务能够有效提升系统与数据的安全性。为了达到这个目的，我们需要执行一系列步骤，包括更新软件包列表、安装OpenSSH服务器和客户端、配置SSH服务以及重启SSH服务。

首先，我们要更新系统的软件包列表，以确保我们可以获取到最新的软件包。在终端中输入以下命令：

sudo apt-get update

接着，我们需要安装OpenSSH服务器和客户端。在终端中输入以下命令：

sudo apt-get install openssh-server openssh-client

接下来，我们需配置SSH服务。编辑/etc/ssh/sshd_config文件，我们会发现默认的SSH配置已经开启，且允许了所有IP地址的访问。我们需要将其更改为仅允许本地主机的访问。将AllowUsers选项更改为None，如下所示：

# /etc/ssh/sshd_config

# Allow users to pass locale environment variables
#Match User anoncvs
#   X11Forwarding no
#   AllowTcpForwarding no
#   PermitTunnel no
#   ForceCommand cvs server

# Change to your default shell
#!/bin/bash

# For this to work you will also need host keys in /etc/ssh/ssh_host_*
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes

# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitTunnel no".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes

# AllowAgentForwarding yes
# AllowTcpForwarding yes
# GatewayPorts no
X11Forwarding yes
# X11DisplayOffset 10
# X11UseLocalhost yes
#PermitTunnel no
#ChrootDirectory none
#VersionAddendum none

#泊松算法
#PrintMotd no
#PrintLastLog yes
#TCPKeepAlive yes
#PermitTTY yes
#ForceCommand cvs server

最后，我们需要重新启动SSH服务以应用更改。在终端中输入以下命令：

sudo systemctl restart ssh

至此，我们已经成功地在Debian系统中安装了SSH服务。现在，你可以使用SSH客户端连接到你的计算机，并利用加密通道进行安全的数据交换。通过配置适当的SSH设置，我们可以更好地保护系统和数据的安全性。