1、在Client上root用戶執行ssh-keygen命令，生成建立安全信任關系的證書。
Client端
# 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): <-- 直接輸入回車
Enter same passphrase again: <-- 直接輸入回車
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：在程序提示輸入passphrase時直接輸入回車，表示無證書密碼。
上述命令將生成私鑰證書id_rsa和公鑰證書id_rsa.pub，存放在用戶家目錄的.ssh子目錄中。
2. 將服務器Client的公鑰證書id_rsa.pub復制到機器Server的root家目錄的.ssh子目錄中
Client端
# scp -p /root/.ssh/id_rsa.pub root@121.40.125.251:/root/.ssh/
root@192.168.0.20's password: <-- 輸入機器Client的root用戶密碼
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
經過以上2步，就在機器Client的root和機器Server的root之間建立安全信任關系。下面我們看看效果：
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，請使用-P參數后跟端口號
Ok!