Linux的核心系统日志文件是/var/log/messages
,它包含了以下内容:
/var/log/messages
是由rsyslogd这个守护进程生成的,如果rsyslogd被停止了,则系统将不会生成新的/var/log/messages
。
last
命令查看Linux系统的登录日志
# last | head
root pts/0 192.168.80.1 Mon Feb 5 11:28 still logged in
root tty1 Mon Feb 5 11:26 still logged in
reboot system boot 3.10.0-693.11.1. Mon Feb 5 11:26 - 11:28 (00:01)
root tty1 Sun Feb 4 11:34 - crash (23:51)
上面的字段从左到右依次为账户名称、登录终端、登录客户端IP、登录时间段。
以上面这4条截取的日志来分析,它们是按时间从新到旧进行排列的,因此我们先从第四条开始分析。第四条日志其实是我在虚拟机以root账户登录后直接关闭虚拟机,因此我们可以发现,账户名称是root,登录终端是tty1(相当于本地登录了),没有客户端IP(因为是本地登录),登录时间段的末尾是crash(因为我不是正常的关机)。
根据上面的逻辑继续来分析就非常清晰了:
另外再介绍一个与登录信息有关的日志文件——/var/log/secure
:
Feb 5 11:28:14 localhost sshd[1462]: pam_unix(sshd:session): session opened for user root by (uid=0)
Feb 5 11:28:14 localhost sshd[1462]: Accepted password for root from 192.168.80.1 port 53703 ssh2
Feb 5 11:26:46 localhost login: ROOT LOGIN ON tty1
Feb 5 11:26:46 localhost login: pam_unix(login:session): session opened for user root by LOGIN(uid=0)
Feb 5 11:26:37 localhost sshd[1102]: Server listening on :: port 22.
Feb 5 11:26:37 localhost sshd[1102]: Server listening on 0.0.0.0 port 22.
Feb 5 11:26:35 localhost polkitd[535]: Acquired the name org.freedesktop.PolicyKit1 on the system bus
Feb 5 11:26:35 localhost polkitd[535]: Finished loading, compiling and executing 2 rules
Feb 5 11:26:35 localhost polkitd[535]: Loading rules from directory /usr/share/polkit-1/rules.d
Feb 5 11:26:35 localhost polkitd[535]: Loading rules from directory /etc/polkit-1/rules.d
Feb 4 21:36:42 localhost sshd[1434]: pam_unix(sshd:session): session closed for user root
对照着last
命令的结果,/var/log/secure
是不是挺容易看明白的呢?