Linux system comes with service list

The/ect/services file lists the system's detailed services

Red font for common services

Acpid

The ACPI (full name Advanced Configuration and Power Interface) service is the power management interface. It is recommended that all notebook users open it. Some servers may not require ACPI. Common operations supported are: "Power switch", "Battery Monitor", "notebook Lid Switch", "Notebook display Brightness", "hibernate", "Hang Up", and so on.

Anacron, ATD, Crond
There is a small difference between these schedulers. It is recommended that you turn on cron, and if your computer will run for a long time, you should turn it on. For servers, you should take a closer look to determine which scheduler should be turned on. In most cases, laptops/desktops should turn off ATD and Anacron. Note: The execution of some tasks requires anacron, such as: clean///var.

Alsasound
ALSA sound card driver daemon. The ALSA sound card driver was originally written for a sound card gravis Ultrasound (GUS) and the program proved to be excellent, so the author started writing drivers for the general sound card. Alsa and Oss/free and Oss/linux are compatible, but have their own interfaces, even better than OSS.

Apmd
Some notebooks and old hardware use APMD. If your computer supports ACPI, you should turn off APMD. If ACPI is supported, then APMD's work will be done by ACPI.

Arptables_jf
Controls the filtering daemon for users of the Arptables network.

Arpwatch
Log and build an Ethernet address and IP address pair database that you see on the LAN interface.

Atalk
AppleTalk the network daemon. Be careful not to run the program in the background, the program's data structure must be initialized before running other processes.

Auditd
The audit subsystem can be used by system administrators to monitor system calls and file system access that is compliant with CAPP or other audit requirements. Its main contents include:

By default, auditing is disabled in the kernel. However, when the AUDITD software is installed, running the software will start the Audit daemon (AUDITD).
When AUDITD is running, the audit information is sent to a User Configuration log file (the default file is/var/log/audit/audit.log). If the AUDITD is not running, the audit information is sent to the syslog. This is done by default settings to put the information into the/var/log/messages. If the audit subsystem is not enabled, no audit information is generated.

These audit information includes the SELinux AVC information. Previously, AVC information was sent to the syslog, but is now sent to the audit log file by the audit daemon.
To disable auditing entirely in the kernel, use the audit=0 parameter when booting. You also need to turn off AUDITD using Chkconfig auditd off 2345来. You can turn off auditing in the kernel at run time using AUDITCTL-E.
The Audit daemon (AUDITD) obtains audit event data from the audit NetLink interface of the kernel. The configuration of the AUDITD will vary, such as the output file configuration and log file disk usage parameters that can be configured in the/etc/auditd.conf file. Please note that if you set up your system for CAPP-style auditing, you must set up a dedicated disk partition to be used only by the audit daemon. This partition should be mounted on the/var/log/audit.

System administrators can also use the Auditctl utility to modify audit parameters, Syscall rules, and file system views of the AUDITD daemon runtime. It includes a sample CAPP configuration that you can copy to/etc/audit.rules to make it work. Audit log data can be viewed and searched through the Ausearch utility.

AutoFS
The service automatically mounts Removable Storage (such as a USB drive). If you use mobile media (such as a removable hard disk, USB flash drive), it is recommended to enable this service.

Avahi-daemon, AVAHI-DNSCONFD
Avahi is the implementation of the ZEROCONF protocol. It can discover devices and services based on the ZEROCONF protocol in a LAN that does not have a DNS service. It's just like MDNS. Unless you have a compatible device or a service that uses the ZEROCONF protocol, you should turn it off.

Bootparamd
A boot parameter server that provides information about the boot required for a diskless workstation on a LAN.

Bluetooth, Hcid, Hidd, SDPD, Dund, Pand
Bluetooth is used for wireless portable devices (non-wifi, 802.11). Many laptops offer Bluetooth support. There are Bluetooth mice, Bluetooth headsets and Bluetooth-enabled phones. Many people don't have Bluetooth devices or Bluetooth-related services, so it should be turned off. Other Bluetooth related services are: Hcid to manage all the visible Bluetooth devices, Hidd support for Input devices (keyboard, mouse), Dund support via Bluetooth dial-up connection network, Pand allows you to connect to Ethernet via Bluetooth.

Capi
is only useful for users who use ISDN devices. Most users should close it.

Chargen
The Chargen server,chargen (Character Generator Protocol) using the TCP protocol is a network service that provides functionality similar to remote typing.

Chargen-udp
Chargen server that uses the UDP protocol.

Chargen-dgram

Chargen-stream

Conman

Cpuspeed
The service can dynamically adjust the frequency of the CPU at run time to conserve energy (power saving). Many notebook CPUs support this feature, and now more and more desktops are supporting this feature. If your CPU is: Petium-m,centrino,amd powernow, Transmetta,intel speedstep,athlon-64,athlon-x2,intel Core 2, you should turn it on. If you want your CPU to run at a fixed frequency, turn it off.

CUPSD, Cups-config-daemon, CUPS-LPD
Printer-related.

Cvs
CVS is a version control system.

Daytime
The daytime daemon, which uses the TCP protocol, provides the client with the ability to obtain the date and time from a remote server. Default port: 13.
Daytime-udp
The daytime daemon using the UDP protocol.

Daytime-dgram
Daytime-stream

Dc_client, Dc_server
The disk cache (Distcache) is used for distributed session caching. Mainly used in SSL/TLS servers. It can be used by Apache. Most desktops should turn it off.

dhcdbd
This is an interface that allows the DBUS system to control DHCP. You can leave the default shutdown state.

Diskdump, Netdump
Disk dumps (Diskdump) are used to help debug kernel crashes. After the kernel crashes it will save a "dump" file for analysis. The network dump (netdump) function is similar to diskdump, except that it can be stored over the network. Unless you are diagnosing kernel-related problems, they should be shut down.

Discard-dgram
Discard-stream

Dnsmasq
DNSMASQ is a lightweight, easy-to-use DNS service tool that can be used for IP address NAT translation at the time of intranet and Internet connection, or as a DNS service for small networks.

Echo ECHO-UDP
The server that uses the UDP protocol echoes the client data Service daemon.
Echo-dgram
Echo-stream

Eklogin
A daemon that accepts rlogin session forensics and a service that is encrypted with KERBEROS5.

Ekrb5-telnet

Firstboot
This service is unique to the Fedora installation process. It performs a specific task that only needs to be performed once at the first boot after installation. It can be turned off.

Functions

Gated
The Gateway Routing daemon. It supports a variety of routing protocols, including RIP versions 1 and 2, the DCN Hello Protocol, OSPF version 2, and EGP versions 2 through 4.

gpm
Terminal mouse pointer support (no graphical interface). If you do not use a text terminal (CTRL-ALT-F1, F2. ), then close it. However, I turned it on at run Level 3 and closed it at run Level 5.

Gssftp
An FTP daemon that uses Kerberos 5 authentication.

Haldaemon
Halt

Hplip, Hpiod, HPSSD
The Hplip service implements HP printer support on Linux systems, including Inkjet,deskjet,officejet,photosmart,business Inkjet and part LaserJet printers. This is the product of HP-sponsored HP Linux print projects (HP Linux Printing project). If you have a compatible printer, enable it.

Hsqldb
A Java relational database daemon named Hypersonic SQL, but the project is no longer in progress.

httpd
Web server Apache daemon that can be used to provide HTML files as well as CGI dynamic content services.

Innd
Usenet news server daemon.

Iiim
Chinese Input Method Server daemon.

inetd
Internet Operation Daemon. Monitor the network's needs for the various services it manages, and start the appropriate service programs when necessary. Replaced by xinetd in Redhat and Mandrake Linux. Debian, Slackware, and SuSE are still used.

Ip6tables
If you do not know if you are using IPV6, in most cases you are not using it. The service is a software firewall for IPV6. Most users should close it.

Ipmi
Iptables
It is the Linux standard firewall (software firewall). If you are connected directly to the Internet (e.g., cable,dsl,t1), it is recommended to turn it on. If you use a hardware firewall (for example: D-link,netgear,linksys, etc.), you can turn it off. It is highly recommended to open it.

IrDA, Irattach
IrDA provides communication support between infrared devices (notebooks, PDAs ' s, mobile phones, calculators, etc.). Most users should close it.

Irqbalance
In a multiprocessor system, enabling the service can improve system performance. Most people don't use multiprocessor systems, so turn it off. But I don't know how it works on multicore CPUs ' s or Hyper-threading CPUs ' s systems. It should not be a problem to shut down in a single CPU system.

Isdn
This is an Internet access method. Unless you use an ISDN cat to surf the internet, you should turn it off.

Keytable
The function of this process is to reprint the keyboard mapping table defined in/etc/sysconfig/keyboards, which can be selected through the Kbdconfig tool. You should make the program active.

Kdump

Klogin
Remote Login daemon.

Krb5-telnet
The Telnet daemon that uses Kerberos 5 authentication.

Kshell
Kshell daemon process.

Killall
krb524
Kudzu
The service is hardware-probed and configured. If you replace the hardware or need to detect hardware changes, turn it on. But most desktops and servers can shut it down and start only when needed.

Ldap
The LDAP (Lightweight Directory Access Protocol) directory accesses the protocol server daemon.

Libvirtd

Lm_sensors
The service can detect the value of the motherboard sensing device or the state of a particular hardware (typically used in a laptop computer). You can check the status of your computer in real-time and learn about your computer's health. It is more popular among GKRELLM users. If there is no special reason, it is advisable to close it.

Lvm2-monitor
Mcstrans
SELinux Conversion Service, if you use SELinux to turn it on, but you can also shut down.

Mdmonitor
This service is used to monitor software RAID or LVM information. It is not a critical service and can be shut down.

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

Messagebus
This is the IPC (interprocess communication, interprocess communication) service for Linux. To be exact, it interacts with DBUS and is an important system service. It is highly recommended to open it.

MULTIPATHD, Microcode_ctl
Can encode and send new micro-code to the kernel to update the Intel IA32 Series Processor Daemon.

Mysqld
A fast, efficient and reliable lightweight SQL database engine daemon.

Named
The DNS (BIND) server daemon.

Netconsole

Netfs
This service is used to automatically mount the shared file space on the network when the system is started, such as: Nfs,samba, and so on. If you connect to another server on the LAN and file sharing, open it. Most desktop and notebook users should turn it off.

NETPLUGD, IFPLUGD
The NETPLUGD is used to monitor the network interface and execute the specified command when the interface state changes. It is recommended to keep its default shutdown state.

Network
Activates/shuts down the various network interface daemons at startup.

NFS, Nfslock
This is the standard file sharing method for the UNIX/LINUX/BSD series operating system. Unless you need to share the data in this way, close it.

Nscd
The service name cache process, which provides faster authentication for services such as NIS and LDAP, and if you run these services, you should turn it on.

Ntpd
The service automatically updates the system time over the Internet. If you can permanently maintain an Internet connection, it is recommended to open it, but not necessary.

NetworkManager, Networkmanagerdispatcher
NetworkManager is a background service program built on the HAL to provide more focused network management capabilities. Including network interface management and network status queries, support for normal network, Dial-Up Networking and wireless networks, many notebook users need to enable this feature, which allows you to switch between the wireless network and the Wired network. Most desktop users should close the service. Additional features such as VPN, DHCP, and DNS are also available.

Pcscd
The service provides smart cards (and is embedded in a credit card, the same size as the small chip of the identification cards) and smart card reader support. If you don't have a reader device, turn it off.

Pcmcia
Mainly used to support the laptop interface daemon.

Portmap
This service is a complement to NFS (file sharing) and NIS (authentication). Unless you are using NFS or NIS services, turn it off.

PostgreSQL
PostgreSQL relational database engine.

PPPoE
The ADSL connection daemon.

Proftpd
PROFTPD is a daemon that configures a flexible FTP server under UNIX.

Psacct
The daemon includes several tools for monitoring process activity, including Ac,lastcomm, Accton, and SA.

Random
A high-quality random number generator that saves and restores the system, which is provided by some random behavior of the system.

Rawdevices
The daemon that is used to load raw devices when using a clustered file system.

Rdisc
Readahead_early, Readahead_later
The service provides performance by preloading specific applications into memory. If you want the program to start faster, turn it on.

Restorecond
Used to monitor and reload the correct file context (filename contexts) for SELinux. It is not required, but if you use SELinux it is strongly recommended to turn it on.

Rhnsd
Red Hat Network Service daemon. Notify the official security information and patch the system.

Routed
The daemon supports automatic IP routing table maintenance for RIP protocol. RIP is primarily used on small networks where a larger network requires a more complex protocol.

RPCGSSD, RPCIDMAPD, RPCSVCGSSD
For NFS V4. Unless you need or use NFS v4, turn it off.

Rsync
Remote sync Data Backup daemon.

Ts.
Start a shell on the remote host and execute the user command.

Rwhod
Allows a remote user to obtain a list of all logged-in users on the machine running the rwho daemon.

Rstatd
A waiting process for collecting and providing system information for other machines on the LAN.

Ruserd
Remote User location service, which is an RPC-based service that provides information about the user that is currently logged to the machine log on the LAN.

Rwalld
Activates the Rpc.rwall service process, an RPC-based service that allows users to write messages to each other terminal that is registered on the LAN machine.

Rwhod
Activates the Rwhod service process, which supports LAN rwho and Ruptime services.

Saslauthd
Use the SASL authentication daemon.

SendMail
Unless you are managing a mail server or you want to deliver or support a shared IMAP or POP3 service within a LAN. Most people don't need a mail transfer agent. If you send and receive mail via the Web (hotmail/yahoo/gmail) or by using the mail transceiver (e.g. Thunderbird, kmail,evolution, etc.). You should close it.

Setroubleshoot
To view the SELinux log program

Squid
The agent server Squid daemon process.

Smartd
The Smart Disk monitoring service is used to monitor and predict disk failures or disk problems (provided that the disks must support SMART). Most desktop users do not need the service, but it is recommended to turn it on, especially the server.

Smb
SAMBA services are the services that are required to share files between Linux and Windows. If a Windows user needs access to a file on Linux, enable it.

Snmpd
Local Simple network management daemon.

Sshd
SSH allows other users to log on to your system and execute the program, which can be the same network as you, or a remote user. There are potential security implications for opening it. If you do not need to be from another machine or do not need to log on remotely, you should close it.

Syslog
Tcpmux-server
Tftp

Time
The daemon obtains the time and date from the remote host, using the TCP protocol.

Time-udp
The daemon obtains the time and date from the remote host, using the UDP protocol.
Time-dgram
Time-stream

Tux
The daemon that runs the Apache server in the Linux kernel.

Vsftpd
Daemon for VSFTPD Server

Vmware-tools
Vmware-tools, the virtual machine is loaded with a vmware-tools package.

Vncserver
VNC (Virtual network Computing), which provides a lightweight protocol that displays the entire "desktop" of a remote computer on a local system.

Winbind
Winbind is a Samba component that is included in the Samba-common package under the CentOS system. Winbind implemented Microsoft RPC call, pluggable authentication module and name Service switch on Linux, and contacted Windows domain control through Samba interface, so that NT domain user can operate as Linux user on Linux host. By setting the NSS configuration of the Linux server, we can allow the system to parse the user information through the Winbind program.

Wpa_supplicant
Wireless network card Internet Service

Xend, Xendomains
Xen Virtual Services Related

Xfs
X Window font server daemon that provides font sets for local and remote x servers.

xinetd
(The service may not be installed by default) it is a special service. It can start multiple services based on requests received from a particular port. For example: A typical Telnet program is connected to Port 23rd. If a telent request is detected by xinetd on Port 23rd, the XINETD will initiate the TELNETD service to respond to the request. For ease of use, you can turn it on. Run Chkconfig--list to know which services are xinetd managed by checking the xinetd related output.

Ypbind
Activates the Ypbind service process for NIS (Network Information System) clients.

Yppasswdd
NIS password Server daemon.

Ypserv
NIS master server daemon.

Yum, yum-updatesd
RPM OS Automatic upgrade and package management daemon.

Linux system comes with service list