Introduction to Linux services-disable unnecessary Linux services

Linux services)It is important for Linux users. Disabling unnecessary services can make Linux run more efficiently, but not all Linux services can be disabled. After installing centos Linux today, we found that many services were started when Linux was started, and most of them did not know what to do. Therefore, I have learned that Linux services can be disabled and those Linux services cannot be disabled at will.

Before shutting down the Linux service, you need to understand some concepts:

1. What is a Linux service/background process (Linux services/daemons)
2. What is the Linux service running level (Linux runlevels)
3. And various tools used to manage Linux services.

Introduction to Linux services management tools:

1. You can use the chkonfig or ntsysv command in the command line to manage Linux services)
2. Use the system-config-services command with a graphical user interface.
3. Gnome users can choose system> Management> Server Settings> services to manage Linux services)

Generally, we recommend that you do not close the following Linux services. They are system-level services, because I am an entry-level Linux player, so I choose not to touch them.

1. Acpid, haldaemon, messagebus, klogd, network, syslogd

 
Acpid, haldaemon, messagebus, klogd, network, syslogd
 

However, the most commonly used Linux service isSshdTo connect to Linux through SSH. This is essential. Therefore, we strongly recommend that you keep this. AndSendmailService. I used centos Linux 5.2. I installed and changed the service by default during installation. Because it is useless, I disabled it. This service is slow enough to start.
Finally, make sure you modify the runtime Level 3 and 5.

Linux services ):NetworkManager, networkmanagerdispatcher
NetworkManager is a background process that automatically switches network connections. Many laptop users need to enable this function, which enables you to switch between a wireless network and a wired network. Most desktop users should disable the service. Some DHCP users may need to enable it.
Linux services ):Acpid
ACPI (full name: Advanced Configuration and power
The service is a power management interface. We recommend that you enable it for all Notebook users. Some servers may not need
ACPI. Common Operations supported include: "Power Switch", "battery monitoring", "notebook lid switch", "laptop display brightness", "Sleep", "hanging up", and so on.

Linux services ):Anacron, ATD, Cron
SchedulingProgramThere is a small difference. Enable
Cron. If your computer is running for a long time, you should turn it on. For servers, you should have a better understanding of which scheduler should be enabled. In most cases, the laptop/desktop should be disabled
ATD and anacron. Note: Anacron is required for executing some tasks, such as cleaning/tmp or/var.

Linux services ):Apmd
Some laptops and old hardware use apmd. If your computer supports ACPI, you should disable apmd. If ACPI is supported, the work of apmd will be completed by ACPI.

Linux services ):Autofs
This service automatically mounts removable storage (such as a USB hard disk ). If you use mobile media (such as mobile hard disks and USB disks), we recommend that you enable this service.

Linux services ):Avahi-daemon, avahi-dnsconfd
Avahi is the implementation of zeroconf protocol. It can discover zeroconf-based devices and services in a LAN without DNS services. It is the same as mdns. Disable it unless you have compatible devices or services that use the zeroconf protocol.

Linux services ):Bluetooth, hcid, hidd, sdpd, Dund, pand
Bluetooth is used for wireless portable devices (non-Wi-Fi,
802.11 ). Many laptops provide Bluetooth support. There are Bluetooth mouse, Bluetooth headset, and mobile phones that support Bluetooth. Many people do not have bluetooth devices or services related to Bluetooth, so they should be disabled. Other Bluetooth Problems
Services include: hcid to manage all visible Bluetooth devices, hidd to provide support for input devices (keyboard, mouse), Dund to connect to the network through Bluetooth dialing, pand
Allow you to connect to Ethernet via Bluetooth.

Linux services ):Capi
It is only useful for users who use ISDN devices. Most users should close it.

Linux services ):Cpuspeed
This service can dynamically adjust the CPU frequency during operation to save energy (power ). CPU of many laptops
Now more and more desktops support this feature. If your CPU is: pew.m, Centrino, amd powernow,
Transmetta, Intel speedstep, Athlon-64, Athlon-X2, Intel Core 2
You should enable it. If you want your CPU to run at a fixed frequency, disable it.

Linux services ):Cron
SeeAnacron.

Linux services ):Cupsd, cups-config-daemon
Printer problems. If you have a cups-compatible printer driven in fedora, you should enable it.

Linux services ):Dc_client, dc_server
The disk cache (distcache) is used for Distributed session cache. It is mainly used for SSL/TLS servers. It can be used by Apache. Most desktops should close it.

Linux services ):Dhcdbd
This is an interface for the guest system to control DHCP. The default off status can be retained.

Linux services ):Diskdump, netdump
Diskdump is used to help debug kernel crashes. After the kernel crashes, it will save a "dump" file for analysis. The netdump function is similar to diskdump, but it can be stored over the network. Unless you are diagnosing kernel-related issues, they should be disabled.

Linux services ):Dund
SeeBluetooth.

Linux services ):Firstboot
This service is unique to the installation process of Fedora. It only needs to execute a specific task once when it is started for the first time after installation. It can be disabled.

Linux services ):GPM
Terminal mouse pointer support (no graphical interface ). If you do not use a text terminal (CTRL-ALT-F1, F2..), close it. However, I enable it at runtime Level 3 and disable it at runtime Level 5.

Linux services ):Hidd
SeeBluetooth.

Linux services ):Maid, hpiod, hpssd
HP printer support in Linux, including
Inkjet, deskjet, officejet, photosmart, business inkjet, and some LaserJet
Printer. This is HP-sponsored HP Linux Printing Project (HP Linux Printing
Project. If you have a compatible printer, enable it.

Linux services ):Iptables
It is a Linux Standard firewall (software firewall ). If you directly connect to the Internet (such as cable, DSL, T1), we recommend that you enable it. If you use a hardware firewall (such as D-Link, Netgear, and Linksys), you can disable it. We strongly recommend that you enable it.

Linux services ):Ip6tables
If you do not know whether you are using IPV6, it is generally not used. This service is a software firewall for IPv6. Most users should close it. Read here to learn how to disable IPv6 Ora's IPv6 support.

Linux services ):IRDA, irattach
IRDA provides communication support between infrared devices (laptops, PDA's, mobile phones, calculators, and so on. Most users should close it.

Linux services ):Irqbalance
In a multi-processor system, enabling this service improves system performance. Most people do not use a multi-processor system, so disable it. But I don't know how it works on the multi-core CPU's or hyper-threading CPU's system. Disabling it in a single CPU system should not cause problems.

Linux services ):ISDN
This is an Internet access method. Unless you use ISDN cat to access the Internet, you should disable it.

Linux services ):Kudzu
This Service performs hardware detection and configuration. If you change the hardware or need to detect hardware changes, enable it. However, most desktops and servers can be shut down and started only when needed.

Linux services ):Lm_sensors
This service can detect the value of the sensor device on the motherboard or the status of specific hardware (usually used in laptops ). You can use it to view the real-time status of your computer and understand its health status. It is popular among gkrellm users. View the lm_sensors homepage for more information. We recommend that you disable it for no special reason.

Linux services ):Mctrans
If you use SELinux, enable it. SELinux is enabled for centos and Fedora Core by default.

Linux services ):Mdmonitor
This service is used to monitor software raid or LVM information. It is not a critical service. You can disable it.

Linux services ):Mdmpd
This service is used to monitor multi-path devices (this type of storage devices can be accessed by more than one controller or method ). It should be disabled.

Linux services ):Messagebus
This is the Linux IPC (interprocess communication) service. Specifically, it interacts with tranquility and is an important system service. We strongly recommend that you enable it.

Linux services ):Netdump
SeeDiskdump.

Linux services ):Netplugd
Netplugd is used to monitor network interfaces and execute specified commands when the interface status changes. We recommend that you keep the default off status.

Linux services ):Netfs
This service is used to automatically mount shared file spaces in the network when the system starts, such as NFS and samba. If you connect to another server in the LAN and share files, enable it. Most desktop and notebook users should disable it.

Linux services ):NFS, nfslock
This is a standard file sharing method for Unix/Linux/BSD operating systems. Disable it unless you want to share data in this way.

Linux services ):Ntpd
The service automatically updates the system time over the Internet. If you can maintain a permanent internet connection, we recommend that you enable it, but it is not necessary.

Linux services ):Pand
SeeBluetooth.

Linux services ):Pcscd
The Service supports Smart Cards (the same size as small chips embedded in credit cards and identification cards) and smart card readers. If you do not have a card reader device, disable it.

Linux services ):Portmap
This service is complementary to NFS (file sharing) and NIS (verification. Disable NFS or NIS unless you use the NFS or NIS service.

Linux services: readahead_early, readahead_later
This service provides performance by pre-loading specific applications to the memory. If you want the program to start faster, enable it.

Linux services ):Restorecond
Used to monitor SELinux and reload the correct file context (File contexts ). It is not necessary, but it is strongly recommended to enable it if you use SELinux.

Linux services ):Rpcgssd, rpcidmapd, rpcsvcgssd
Used for NFS V4. Disable NFS V4 unless you need it or use it.

Linux services ):Sendmail
Unless you manage an email server or you want to transmit or support a shared IMAP or pop3 in the LAN
Service. Most people do not need an email transmission proxy. If you use a web page (Hotmail/Yahoo/Gmail) or
For example, Thunderbird, kmail, and evolution. You should close it. (I am using centos
In 5.2, the service was automatically installed and disabled)

Linux services ):Smartd
The smart disk monitoring service is used to monitor and predict disk failures or disk problems (prerequisite: the disk must support smart ). Most desktop users do not need this service, but we recommend that you enable it, especially for servers.

Linux services ):SMB
The Samba service is required for file sharing between Linux and Windows. If a Windows user needs to access a file on Linux, enable it.

Linux services ):Sshd
SSH allows other users to log on to your system and execute programs. The user can be a network or remote user. Enabling it has potential security risks. If you do not need to log on from another machine or remotely, disable it. I strongly recommend that you retain the service, or you cannot use the sshd service in Linux.

Linux services ):Xinetd
(This service may not be installed by default) it is a special service. It can start multiple services according to the requests received by a specific port. For example, a typical telnet program connects to 23
Port number. If a Telent request is detected by xinetd on port 23, xinetd will start telnetd
Service to respond to this request. You can enable it for ease of use. Run chkconfig-list and check the output related to xinetd to find out which services are
Xinetd management.