SSH远程免密登录
环境：两台centos虚拟机，一台为192.168.134.129（用作远程主机），另一台为192.168.134.130.
首先查看一下两台linux的ip地址：
[root@promote ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.134.129 netmask 255.255.255.0 broadcast 192.168.134.255
inet6 fe80::4881:9be0:2bb6:62e prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:eb:2d:01 txqueuelen 1000 (Ethernet)
RX packets 145 bytes 18326 (17.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 144 bytes 23724 (23.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 64 bytes 5696 (5.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 64 bytes 5696 (5.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
再来看一下另外一台：
[root@machine1 ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.134.130 netmask 255.255.255.0 broadcast 192.168.134.255
inet6 fe80::4881:9be0:2bb6:62e prefixlen 64 scopeid 0x20<link>
inet6 fe80::134a:dd7d:6b15:96ea prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:42:f7:1d txqueuelen 1000 (Ethernet)
RX packets 127 bytes 15748 (15.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 134 bytes 21258 (20.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 64 bytes 5696 (5.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 64 bytes 5696 (5.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
先在192.168.134.130上远程登录192.168.134.129试试。
[root@machine1 ~]# ssh 192.168.134.129
The authenticity of host '192.168.134.129 (192.168.134.129)' can't be established.
ECDSA key fingerprint is SHA256:JqAC8jcLCLobvRy0wzY9VGBNuZU3EydpO8n2fEtQ178.
ECDSA key fingerprint is MD5:5d:26:a1:60:c3:eb:02:e9:97:7a:bb:7a:49:8a:14:0b.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.134.129' (ECDSA) to the list of known hosts.
root@192.168.134.129's password:
发现是要输入密码才可以登录的。
现在来实现免密登陆。
首先在192.168.134.130上生成公钥。
[root@machine1 ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
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:
SHA256:pRHW15F3aA7esrPe39CEchPqzPCKAIKd/+4liaigyzo root@machine1
The key's randomart image is:
+---[RSA 2048]----+
| o. ..+ |
| . .. o = o|
| . .o =...|
| o . + o.oo |
|. + . S . oo+ .|
| + o . *oo + |
|. . o + . =o. .|
|E. . + . ... ..|
|*+ o+ . ... ..o|
+----[SHA256]-----+
接着将此公钥发送到远程主机192.168.134.129。
[root@machine1 ~]# ssh-copy-id 192.168.134.129
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.134.129's password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh '192.168.134.129'"
and check to make sure that only the key(s) you wanted were added.
传送完成之后，到远程主机192.168.134.129上修改ssh的配置文件/etc/ssh/sshd_config.
修改以下两条：PubkeyAuthentication yes和PasswordAuthentication no,即密钥登陆改为yes，密码登陆改为no.
接着重启一下sshd服务
[root@machine1 ~]# systemctl restart sshd
然后到192.168.134.130上远程免密登录192.168.134.129试试。
[root@machine1 ~]# ssh 192.168.134.129
Last login: Thu Jul 12 00:01:07 2018 from 192.168.134.1
[root@promote ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.134.129 netmask 255.255.255.0 broadcast 192.168.134.255
inet6 fe80::4881:9be0:2bb6:62e prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:eb:2d:01 txqueuelen 1000 (Ethernet)
RX packets 1927 bytes 207095 (202.2 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1693 bytes 174581 (170.4 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 64 bytes 5696 (5.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 64 bytes 5696 (5.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
免密登录成功！