SSH

OpenSSH

  • Remote operations are done using ssh, scp, and sftp.
  • Key management with ssh-add, ssh-keysign, ssh-keyscan, and ssh-keygen.
  • The service side consists of sshd, sftp-server, and ssh-agent.

基本用法

ssh root@ip 或 ssh -l root -p 22 ip

  • -l Specifies the user to log in as on the remote machine.
  • -p Port to connect to on the remote host.
  • -f Requests ssh to go to background just before command execution.
  • -C Requests compression of all data.
  • -N Do not execute a remote command. This is useful for just forwarding ports.
  • -R remote (server) host are to be forwarded to the local side.
  • -L local (client) host are to be forwarded to the given host and port, or Unix socket, on the remote side.

重启

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service sshd restart
或
systemctl restart sshd

相关配置

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grep -v '^\s*$\|^\s*\#' /etc/ssh/sshd_config

UsePrivilegeSeparation

连接慢

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GSSAPIAuthentication no
UseDNS no

修改端口

https://www.cyberciti.biz/faq/howto-change-ssh-port-on-linux-or-unix-server/

免密码登录

  1. 生成公钥
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cd ~/.ssh
ssh-keygen -t rsa
  1. 传输公钥至服务器
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scp id_rsa.pub root@ip:~/.ssh
cat id_rsa.pub >> authorized_keys

ssh-keyscan

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ssh-keyscan -H -t rsa ip >> known_hosts
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cat /var/run/sshd.pid
kill $(cat /var/run/sshd.pid)

idle timeout for OpenSSH

端口转发

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ssh -N -L*:80:localhost:9600 root@localhost

autossh 自动重连

主页 https://www.harding.motd.ca/autossh/
文档 https://www.harding.motd.ca/autossh/README.txt

安装

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Linux   yum -y install autossh
macOS   brew install autossh

使用

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autossh -M 10010 -N root@ip

autossh -M 5122 -N -L2001:localhost:22 root@ip
ssh root@127.0.0.1 -p 2001

https://stackoverflow.com/questions/25084288/keep-ssh-session-alive

ssh NAT traversal

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ssh -N -R8887:localhost:8000 root@ip
ssh root@ip
ssh -N -L*:80:localhost:8887 root@localhost
http://ip/

autossh -M 5122 -N -L2001:localhost:22 root@localhost
ssh -N -L*:80:localhost:8887 root@localhost

sftp

Compared to the SCP protocol, which only allows file transfers, the SFTP protocol allows for a range of operations on remote files which make it more like a remote file system protocol. An SFTP client’s extra capabilities include resuming interrupted transfers, directory listings, and remote file removal.

参考