Linux system security optimization in several directions

1. Streamlined installation package (minimized installation) 2. Disable booting services that do not need to be started 3. Optimize kernel parameters /etc/sysctl.conf4. Add system file descriptors, stacks, etc. 5. Disable root startup, modify The SSH port is a special port. 6. The machine with external network IP should open the configuration firewall, configure SELINUX7. Clear the useless default system account or group (not required) 8. Lock sensitive files, such as /etc/passwd (not required) 9. Configure server and Internet time Synchronize. 10. Configure sudo to fine-tune the normal user permissions.

setup or chkconfig removes the service that does not have to be started by booting chkconfig –list