Liunx System Service View and management commands, liunx System Service

Liunx System Service View and management commands, liunx System Service
Daemon and service)Main daemon categories

Stand_alone: This daemon can independently start the service.

Super daemon: A special daemon for unified management

There are two processing modes for super daemon:

Multi_threaded (multithreading)

Single_threaded (single thread)

Deamon work type

Signal-control Immediate Processing

Interval-control specified time processing (crond)

 

Service view the corresponding service and port, you can directly modify

Cat/etc/services

Service [service name]) (start | stop | restart ....)

Parameters:

Service name: the name of the service to be started. It must correspond to/etc/init. d.

Start |... That is, the work to be done by the Service.

-- Status-all: lists all the service statuses of stand alone in the system.

Service firewall management xinetd, TCP Wrappers

System firewall analysis can be performed through data packet filtering or software analysis.

The default liunx tool is/etc/hosts. deny and/etc/hosts. allow configuration files.

Any service managed by Xinetd can use these two files to set the Firewall

/Etc/hosts. allow and/etc/hosts. deny are the configuration files of/usr/sbin/tcpd (software for analyzing TCP packets ).

Items allowed by/etc/hosts. allow. This file has a higher priority than the deny file

/Etc/hosts. deny operation not allowed

Control using TCP Wrappers:

1. Source IP address or/IP address segment of the entire domain

2. port (service)

Configuration File Syntax

<Service >:< IP, domain, hostname >:< action>

<Service >:< IP, domain, host name >:< operation ># the preceding <> does not exist in the configuration file

Example: rsync: 127.0.0.1: deny

 

Special Functions of TCP Wrappers

Spawn (action)

# The subsequent shell can be used for additional work and has the variable function. The main variable content is: % h (hostname) % a (address) % d (daemon)

Twist (action)

Execute the command immediately and disconnect after execution.

Chkconfig manages whether the system service is enabled by default.

Chkconfig -- list view all services

Chkconfig -- list [service name] to view the service status

Chkconfig [-- level [0123456] [service name] [on | off] sets a service to start or close at this level