1. Remove unnecessary users and user groups
2. Turn off services not required by the system
3. Modify the default SSH login port to prevent root login
4, without root, add ordinary user, through sudo authorization management, reasonable use SU
5, turn off SELinux
6, turn on iptables (if it is high concurrency, close)
7, password Security Policy and method (password authentication method)
8, reasonable use of shell history command logging function
9. Delete Welcome login information (/etc/issue)
10, enable Tcp_wrappers
11. Lock key files with chattr (password file, log file, history file)
12, security measures for/TMP/VAR/TMP/DEV/SHM (/etc/fstab)
13, use domestic yum, quick Install
14 Timer Update time server (time.nist.gov)
Linux kernel parameter optimization (adjusts/etc/sysctl.conf based on service type)
16 Adjustment file Descriptor (/etc/security/limits.conf)
Important levels
This article is from the "Crazy_sir" blog, make sure to keep this source http://douya.blog.51cto.com/6173221/1660530
Linux System optimization Items