Linux start-up process and need to boot service to explain and modify and firewall

The boot process from boot to login for Linux systems.

1. Boot BIOS self-test

2.MBR Boot

3.grub boot Menu

4. Load Kernel kernel

5. Start the INIT process

6. Read Inittab files, execute scripts such as RC.SYSINIT,RC

7. Start Mingetty, enter the system login screen

Thin boot system boot, necessary to keep the boot up:

1, sshd

Remote connection to a Linux Server service program

2, Rsyslog

Operating system provides a mechanism that the system daemon will typically use Rsyslog

Store all kinds of information in the system log file, CENTOS6 formerly the name of this service is syslog

3. Network

Activation, Network

4, Crond

This service is used for periodic execution of system and user-configured task schedules.

The software that must be used in the production environment.

5, Sysstat

A set of tools for detecting system performance and efficiency. such as CPU usage, hard drives, and network throughput data.

Through the analysis of these data to determine whether the system is normal.

1) Iostat tool provides data on CPU usage and drive throughput efficiency:

2) The Mpstat tool provides data related to single or multiple processors:

3) The SAR tool is responsible for collecting, reporting and storing information about system activity.

The system is temporarily reserved for five.

To modify the boot Start method:

1. Setup System Services 2, Ntsysv ibid.

Chkconfig--list to see which service the service is booting on

To enable the boot only sshd|network|rsyslog|crond|sysstat command:

For name in ' Chkconfig--list|awk ' {print '} ' |grep-ev ' Sshd|network|rsyslog|crond|sysstat ';d o chkconfig $name off;done

Chkconfig Set Boot start

Linux optimized iptables firewall processing

IPTABLES-L-N View Firewall

/etc/init.d/iptables Status View state

Shut down firewall:/etc/init.d/iptables stop

Linux start-up process and need to boot service to explain and modify and firewall