ssh自动登录的4种实现方法

1. 自动ssh/scp方法

a为本地主机(即用于控制其他主机的机器) ;
b为远程主机(即被控制的机器server), 假如ip为192.168.60.110;
a和b的系统都是linux

在a上运行命令:
# ssh-keygen -t rsa (连续三次回车,即在本地生成了公钥和私钥,不设置密码)
# ssh root@192.168.60.110 "mkdir .ssh" (需要输入密码)
# scp ~/.ssh/id_rsa.pub root@192.168.60.110:.ssh/id_rsa.pub (需要输入密码)

在b上的命令:
# touch /root/.ssh/authorized_keys (如果已经存在这个文件, 跳过这条)
# cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys (将id_rsa.pub的内容追加到authorized_keys 中)

回到a机器:
# ssh root@192.168.60.110 (不需要密码, 登录成功)

2. 控制n个机器如上所述自动登录

那就需要n对钥匙(密钥和公钥), ssh-keygen 命令可以随意更改钥匙对的名字, 比如:
# ssh-keygen -t rsa
generating public/private rsa key pair.
enter file in which to save the key (/root/.ssh/id_rsa): /root/.ssh/id_rsa_192.168.60.110

这样私钥和公钥的名字分别就是: id_rsa_192.168.60.110和 id_rsa_192.168.60.110.pub;然后将 id_rsa_192.168.60.110.pub 文件的内容, 追加到sever的 ~/.ssh/authorized_keys文件中,最后, 在本地用ssh命令的 -i 参数指定本地密钥, 并登录:
# ssh -i /root/.ssh/id_rsa_192.168.60.110 someone@192.168.60.110

scp也是一样的
# scp -i /root/.ssh/id_rsa_192.168.60.110 filename someone@192.168.60.110:/home/someone

在文件.bashrc中加下两行，每次做同样的操作就不用敲入这样长的命令了：
alias sshcell='ssh -i /root/.ssh/id_rsa_192.168.60.110 someone@192.168.60.110'
alias scpcell='scp -i /root/.ssh/id_rsa_192.168.60.110 filename someone@192.168.60.110:/home/someone'

这样，直接键入一下指令实现ssh和scp自动登录：
# sshcell
# scpcell

3. 自动ssh/scp脚本

如果需要从a，到b，然后才能够到c，那么需要ssh和scp两次，是比较麻烦的。
ssh自动登录：
#!/usr/bin/expect -f
set timeout 30
spawn ssh weiqiong@b
expect "password:"
send "ppppppr"
expect "]*"
send "ssh weiqiong@cr"
expect "password:"
send "ppppppr"
interact

scp从a拷贝文件到c：
#!/usr/bin/expect -f
set timeout 300
set file [lindex $argv 0]
spawn scp $file weiqiong@b:/home/weiqiong
expect "password:"
send "ppppppr"
expect "]*"
spawn ssh weiqiong@b
expect "password:"
send "ppppppr"
expect "]*"
send "scp $file weiqiong@c:/home/weiqiongr"
expect "password:"
send "ppppppr"
expect "]*"
exit
interact

scp从c拷贝文件到a：
#!/usr/bin/expect -f
set timeout 300
set file [lindex $argv 0]
spawn ssh weiqiong@b
expect "password:"
send "ppppppr"
expect "]*"
send "scp weiqiong@c:/home/weiqiong/$file .r"
expect "password:"
send "ppppppr"
expect "]*"
send "exitr"
expect "]*"
spawn scp weiqiong@b:/home/weiqiong/$file .
expect "password:"
send "ppppppr"
interact

4. 建立ssh/scp通道

比如说我的机器是a，中间服务器为b，目标服务器是c
从a可以ssh到b，从b可以ssh到c，但是a不能直接ssh到c
现在展示利用ssh通道技术从a直接传输文件到c

1. ssh -l1234:c:22 userid@b
input b's password
(1234是本机a的空闲端口，该指令需要a机器上的root用户权限，实际上是在本机1234端口建立了一个通道)

2. 打开一个新的console，键入：
scp -p1234 filename userid@localhost:
input c's password