#####sshd服务#####
实验环境:
nm-connection-editor
ifconfig
##1.sshd简介###
sshd= secure shell
可以通过网络在主机中开机shell的服务
客户端软件
sshd
连接方式:
ssh username@ip ##文本模式的连接
ssh -X username@ip ##可以在连接成功后开机图形
注意:
第一次连接陌生主机是要建立认证文件
所以会询问是否建立,需要输入yes
在次连接此台主机时,因为已经生成~/.ssh/know_hosts文件所以不需要再次yes
远程复制:
scp file root@ip:dir ##上传
scp -r root@ip:file dir ##下载
###2.sshd的key认证####
1.生成认证KEY
[root@server ~]# ssh-keygen ##生成密钥的命令
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): ##指定保存加密字符的文件(使用默认)
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): ##设定密码(使用空密码)
Enter same passphrase again: ##确认密码
Your identification has been saved in "/root/.ssh/id_rsa." ##密钥(钥匙)
Your public key has been saved in "/root/.ssh/id_rsa.pub." ##公钥(锁)
The key fingerprint is:
30:42:a5:0e:ae:8c:bf:ed:99:4d:7b:8c:93:a3:46:1e [email protected]
The key's randomart image is:
+--[ RSA 2048]----+
| ... |
| . . |
| . o o |
| . o . o |
| . . S |
|o. E |
|o. o ..+ |
| . .o==.o |
| o+*.o+ |
+-----------------+
2.加密服务
[root@server ~]# ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected] ##加密sshd服务
The authenticity of host '172.25.254.111 (172.25.254.111)' can't be established.
ECDSA key fingerprint is 7d:cf:00:59:99:b9:b3:4e:40:33:f1:4f:9f:54:b6:58.
Are you sure you want to continue connecting (yes/no)? yes
/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
[email protected]'s password:
Number of key(s) added: 1/roo
Now try logging into the machine, with: "ssh '[email protected]'"
and check to make sure that only the key(s) you wanted were added.
[root@server ~]# ls /root/.ssh/
authorized_keys id_rsa id_rsa.pub known_host
^
此文件出现表示加密完成
3.分发钥匙
[root@server ~]# scp /root/.ssh/id_rsa [email protected]:/root/.ssh/
4.测试
在客户机中(172.25.254.100)
ssh [email protected] ##连接时发现直接登陆不需要root登陆系统的密码认证
#####3.sshd的安全设定#####
vim /etc/ssh/sshd_config
78 PasswordAuthentication yes yes|no ##是否允许用户通过登陆系统的密码做sshd的认证
48 PermitRootLogin yes|no ##是否允许root用户通过sshd服务的认证
52 Allowusers student westos ##设定用户白名单,白名单出现默认,不在白名单的用户不能使用sshd
53 Denyusers westos ##设定用户黑名单,黑名单出现默认不在黑名单的用户可以使用sshd
#####4.添加sshd登陆信息########
vim /etc/motd ##文件内容就是登陆后显示的信息
####5.用户的登记审计#######
1.w ##查看正在使用当前系统的用户
-f ##查看使用来源
-i ##显示IP
/var/run/utmp
2.last ##查看使用过并退出的用户信息
/var/log/wtmp
3.lastb ##试图登陆但没成功的用户
/var/log/btmp