linux SSH连接banner设置_是否设置ssh警告banner

目的

SSH连接banner设置的目的：
在SSH连接成功后了解服务器地址，期限，拥有者，服务器硬件配置，环境变量等重要信息

未设置前雨云服务器SS连接成功后展示的内容

WARNING! The remote SSH server rejected X11 forwarding request.
Linux RainYun-SHrBEyXy 5.10.0-28-amd64 #1 SMP Debian 5.10.209-2 (2024-01-31) x86_64
Welcome to RainYun Cloud Services                                                                                                                                                    
Check out the latest activities or get help from: https://www.rainyun.com
Last login: Wed Aug 17 21:26:05 2022
1
2
3
4
5

流程

本文会实现linux中设置ssh登录时显示的banner自定义 启用Banner功能，编辑/etc/ssh/sshd_config文件

sudo vim /etc/ssh/sshd_config
1

文件中找到Banner选项（如果存在），并取消注释。 如果Banner选项不存在，请将其添加到文件中。例如：

Banner /etc/ssh/banner.txt
1

上传/etc/ssh/banner.txt文件到 /etc/ssh目录下
重新启动SSH服务以使更改生效。在大多数Linux发行版中可以使用以下命令重启SSH服务：

sudo systemctl restart ssh
1

或者

sudo service ssh restart
1

如果找不到ssh,则使用sudo systemctl restart sshd或者sudo service sshd restart

增加banner后，尝试SSH连接

Connecting 
Connection established.
To escape to local shell, press 'Ctrl+Alt+]'.

   _                            
 | |__     ___   _ __     __ _ 
 | '_ \   / _ \ | '_  \  / _  |
 | | | | |  __/ | | | | | (_| |
 |_| |_|  \___| |_| |_|  \__, |
                         |___/ 
_________________________________________
Manger: liheng
Aera: America
Service providers: yuyun
System: CentOS Linux 7
CPU：Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz
Memory: 1.8G
Create_time: 2024-04-14
End_time: 2024-06-18
Environment: Nginx,Mysql,node
_________________________________________
WARNING! The remote SSH server rejected X11 forwarding request.
Last failed login: Fri May 10 13:41:14 CST 2024 from 180.101.88.245 on ssh:notty
There were 314 failed login attempts since the last successful login.
Last login: Fri May 10 12:23:27 2024 from 120.227.56.80
[root@RainYun-Q7c3pCXM ~]# 

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

FAQ

SSH名称

若出现以下输出，则系统中没有名为ssh.service的systemd单元

[root@RainYun-Q7c3pCXM ~]# sudo systemctl restart ssh
Failed to restart ssh.service: Unit not found.
[root@RainYun-Q7c3pCXM ~]# sudo service ssh restart
Redirecting to /bin/systemctl restart ssh.service
Failed to restart ssh.service: Unit not found.
[root@RainYun-Q7c3pCXM ~]# 
1
2
3
4
5
6

检查SSH服务是否已安装： 使用以下命令检查SSH服务是否已安装：

rpm -qa | grep openssh-server
1

若有则如下输出

[root@RainYun-Q7c3pCXM ~]# rpm -qa | grep openssh-server
openssh-server-7.4p1-23.el7_9.x86_64
1
2

则尝试使用
启用并启动SSH服务： 使用以下命令启用并启动SSH服务

sudo systemctl enable sshd
sudo systemctl start sshd
1
2

目前仅发现1个异常，欢迎评论增加FAQ