两台服务器之间免密码传输文件scp ssh

原理就是把两台服务器的对应用户的公钥拷贝到对方authorized_keys文件里面！

​Client端​

步骤1(生成证书)

ssh-keygen  -t rsa

Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase):            <-- 直接输入回车
Enter same passphrase again:                           <-- 直接输入回车
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
49:9c:8a:8f:bc:19:5e:8c:c0:10:d3:15:60:a3:32:1c root@Server

​注意：​ 在程序提示输入passphrase时直接输入回车，表示无证书密码。

上述命令将生成私钥证书 ​id_rsa​ 和公钥证书 ​id_rsa.pub​ ，存放在用户家目录的.ssh子目录中。

步骤2（copy证书）

将​Client​服务器的公钥证书​id_rsa.pub​复制到​Server​服务器的​root​家目录的 ​.ssh​ 子目录中

​Client端​

scp -p /root/.ssh/id_rsa.pub root@121.40.125.251:/root/.ssh/

下面命令如果不成功，请手动一出去后复制到另外一台服务端

root@192.168.0.20's password:          <-- 输入机器Client的root用户密码
   id_rsa.pub           100% |**************************|   218       00:00

​Server端​

mv /root/.ssh/id_rsa.pub /root/.ssh/authorized_keys   
或者 
cat id_rsa.pub >>authorized_keys

经过以上2步，就在机器Client的root和机器Server的root之间建立安全信任关系。下面我们看看效果：

​Client端​

scp -i  /root/ .ssh/id_rsa text  root@192.168.0.20:/root
   text                 100% |**************************|    19       00:00

​若ssh端口非22端口，请使用-P参数后跟端口号！​

使用问题：

1、​Add correct host key in /root/.ssh/known_hosts to get rid of this message​

bug：

Add correct host key in /root/.ssh/known_hosts to get rid of this message

解决办法：

rm ~/.ssh/known_hosts