环境如下:
A机器两块网卡eth0(192.168.0.173)、eth1(192.168.100.1),eth0可以上外网,eth1仅仅是内部网络,B机器只有eth1(192.168.100.3),和A机器eth1可以通信互联,外网无法ssh进入B主机,可以使用ssh的反向隧道实现。
A:
1、首先在A 上编辑sshd 的配置文件/etc/ssh/sshd_config,将GatewayPorts 开关打开:
vim /etc/ssh/sshd_config
GatewayPorts yes
2、重启sshd服务,使用修改生效
systemctl restart sshd
ssh -ngfNTR 1222:192.168.100.3:22 [email protected] -o ServerAliveInterval=300
-f 表示后台执行
-N 表示不执行任何命令
-R 建立反向隧道
1222 A机用来外面ssh的监听端口
-o ServerAliveInterval=300 的意思是让ssh client每300秒就给server发个心跳,以免链路被RST.
-f Requests ssh to go to background just before command execution. 让该命令后台运行 .
-n Redirects stdin from /dev/null (actually, prevents reading from stdin).
-N Do not execute a remote command. 不执行远程命令 .
-T Disable pseudo-tty allocation. 不占用 shell .
-g Allows remote hosts to connect to local forwarded ports.
[[email protected] ~]# netstat -antp | grep 1222
tcp 0 0 0.0.0.0:1222 0.0.0.0:* LISTEN 16182/sshd: root
tcp6 0 0 :::1222 :::* LISTEN 16182/sshd: root
3、外部主机连接B就直接连接A的1222端口就可以了,1222要被防火墙允许
ssh -p 1222 [email protected]
[email protected]:/mnt/c/Users/aikera# ssh -p 1222 [email protected]
Last failed login: Tue Feb 13 11:19:53 CST 2018 from gateway on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Tue Feb 13 10:52:09 2018 from gateway
[[email protected] ~]#
4、A上查看端口的监听状态:
[[email protected] ~]# netstat -antp | grep 1222
tcp 0 0 0.0.0.0:1222 0.0.0.0:* LISTEN 16182/sshd: root
tcp 0 0 192.168.0.173:1222 192.168.0.190:60738 ESTABLISHED 16182/sshd: root
tcp6 0 0 :::1222 :::* LISTEN 16182/sshd: root
5、保持连接
我们需要这个隧道能够一直保持连接状态,在需要的时候可以随时接入,我们需要安装使用autossh
B:
yum install autossh -y
B:
autossh -p 22 -M 6777 -fNR 1322:127.0.0.1:22 [email protected] #-M 参数指定的端口用来监听隧道的状态,与端口转发无关;同时需要在A防火墙打开1322端口主机之间可以使用不用密码的key
The authenticity of host ‘192.168.0.173 (192.168.0.173)‘ can‘t be established.
ECDSA key fingerprint is d5:1c:36:d7:57:64:3d:5b:8a:e8:aa:93:54:1d:8c:22.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘192.168.0.173‘ (ECDSA) to the list of known hosts.
Enter passphrase for key ‘/root/.ssh/id_rsa‘:
A:
[[email protected] ~]# netstat -antp | grep 1322
tcp 0 0 0.0.0.0:1322 0.0.0.0:* LISTEN 16798/sshd: root
tcp6 0 0 :::1322 :::* LISTEN 16798/sshd: root
外面ssh B:
[email protected]:/mnt/c/Users/aikera# ssh -p 1322 [email protected]
[email protected]‘s password:
Last login: Tue Feb 13 15:29:30 2018 from gateway
[[email protected] ~]#
添加服务:
B:
useradd autosshuser
passwd autosshuser
su - autossh
ssh-keygen -t rsa #生成密匙对,按回车,不使用密码的密匙对
ssh-copy-id [email protected] #copy密匙到A
B
创建以autosshuser 用户权限调用autosshd 的service 文件。将下面文本写入到文件/lib/systemd/system/autosshd.service,并设置权限为644:
[Unit]Description=Auto SSH Tunnel
After=network-online.target
[Service]
User=autosshuser
Type=simple
ExecStart=/bin/autossh -p 22 -M 5689 -NR ‘*1322:127.0.0.1:22‘ [email protected] -i /home/autossh/.ssh/id_rsa
ExecReload=/bin/kill -HUP $MAINPID
KillMode=process
Restart=always
[Install]
WantedBy=multi-user.target
WantedBy=graphical.target
systemctl enable autosshd #允许自启动
systemctl start autosshd
A
使用这条反向隧道穿透B 所在的NAT SSH 连接到B
ssh -p 1322 [email protected]
外部:
ssh -p 1322 [email protected]
C主机:
通过ssh做端口转发代理上网:
ssh -p 1322 -qngfNTD 3128 [email protected]
C 是外面的电脑,A 是你的云主机,B 是你公司的电脑。这样做就可以给浏览器设置端口为3128 的sock4 本地(127.0.0.1)代理
浏览公司内网web
原文地址:http://blog.51cto.com/m51cto/2071530