windows putty 连接到 linux 免密码

目标：system1透过ssh链接到system2电脑

• 生成 private key (id_rsa) & public key (id_rsa.pub)
• id_rsa是system1要用的，例如windows端
• id_rsa.pub是你要连过去system2要用的, 此服务器必须安装openssh-server服务(sshd)
• 把id_rsa.pub append到system2的 ~/.ssh/authorized_keys 文件里面
• 并要清楚登入服务器的username，例如root
• 找一台能够运行 ssh-keygen 的环境, windows可用Cygwin

步骤以下：

# ssh-keygen -t rsa
Enter file in which to save the key (~/.ssh/id_rsa): Created directory '~/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in ~/.ssh/id_rsa. Your public key has been saved in ~/.ssh/id_rsa.pub. The key fingerprint is: 1c:fe:8d:10:b5:32:09:95:51:48:df:45:ef:74:5d:dc henry@db0222da7529 The key's randomart image is: +--[ RSA 2048]----+ | .o+=o .o.o| | .o+ o . .E| | * o . =| | o = o.| | S .| | o o | | o . | | | | | +-----------------+

ssh-keygen的参数说明：

-t type
  Specifies the type of key to create. The possible values are
  ``rsa1'' for protocol version 1 and ``dsa'', ``ecdsa'' or ``rsa''
  for protocol version 2.

# cat ~/.ssh/id_rsa.pub > ~/.ssh/authorized_keys

注意: 用putty自带的PUTTYGEN.EXE生成会不兼容OpenSSH，从而会致使登陆时出现server refused our key错误

作法: 把private key(id_rsa)给拷贝出来，我是用vim或cat来开启id_rsa文件而后用鼠标按右键拷到windows下的剪贴板, 存到一个文本给PUTTYGEN.EXE File/Load private key使用. 接着点击Save private key, 此档案等下要用.

1.开启putty.exe, 设定Connection/data/Auto-login username, 这里我是用root来登入

2.SSH/Auth/Private key file for authentication:点击Browser选择到你保存私钥(.pkk)的文件, 就是 Save private key 的那个档案.