Debian Linux安装OpenSSH(sshd-server)
您需要使用apt-get或aptitude命令在Debian Linux下安装OpenSSH服务器。
打开终端并键入以下命令以root用户身份更新包数据库：
# apt-get update
任务：在Debian Linux下安装OpenSSH服务器
键入以下命令：
# apt-get install openssh-server
...
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
ssh-askpass rssh molly-guard ufw
The following NEW packages will be installed:
openssh-server
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 318 kB of archives.
After this operation, 717 kB of additional disk space will be used.
Get:1 http://mirror.anl.gov/debian/ squeeze/main openssh-server amd64 1:5.5p1-6+squeeze1 [318 kB]
Fetched 318 kB in 3s (89.0 kB/s)
Preconfiguring packages ...
Selecting previously deselected package openssh-server.
(Reading database ... 153448 files and directories currently installed.)
Unpacking openssh-server (from .../openssh-server_1%3a5.5p1-6+squeeze1_amd64.deb) ...
Processing triggers for man-db ...
Setting up openssh-server (1:5.5p1-6+squeeze1) ...
Creating SSH2 RSA key; this may take some time ...
Creating SSH2 DSA key; this may take some time ...
Restarting OpenBSD Secure Shell server: sshd.默认情况下，openssh将在TCP端口22上运行。您可以使用以下命令对其进行验证：示例输出：
# netstat -tulpn | grep :22
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 3946 / sshd
tcp6 0 0 ::: 22 ::: * LISTEN 3946 / sshd
您可以连接到Openssh服务器，键入：
$ ssh user@localhost
$ ssh user@sever-ip-here
如何在Debian Linux下启动/停止/重启OpenSSH服务器？
以root用户身份键入以下命令：OR 示例会话：
# service ssh stop
# service ssh start
# service ssh restart
# service ssh status
# /etc/init.d/ssh stop
# /etc/init.d/ssh start
# /etc/init.d/ssh restart
# /etc/init.d/ssh status
如何在防火墙级别打开端口22？
编辑防火墙脚本并附加以下规则以限制对192.168.1.0/24的访问：
/sbin/iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 22 -j ACCEPT保存并关闭文件。或者，您可以按如下方式键入命令并将其保存到防火墙配置文件中：
＃/sbin/iptables -A INPUT -s 192.168.1.0/24 -m state --state NEW -p tcp --dport 22 -j ACCEPT
＃iptables-save > /path/to/your.firewall.conf如何在Debian Linux下配置和保护OpenSSH服务器？
您需要使用文本编辑器（如vi，run）编辑/ etc / ssh / sshd_config文件：
# vi /etc/ssh/sshd_config
请参阅此文章解释配置选项以进行调整以提高OpenSSH服务器安全性。
翻译来源：https://www.cyberciti.biz/faq/debian-linux-install-openssh-sshd-server/