acpid
This a completely flexible, totally extensible daemon for delivering ACPI events. It listens on a file (/proc/acpi/event) and when an event occurs, executes programs to handle the event.
ACPI stands for: Advanced Configuration and Power Interface.
aep1000
For AEP 1000 coprocessors. It's used for hardware cryptographic acceleration under Linux.
anacron
Anacron is a periodic command scheduler. It executes commands at intervals specified in days. Unlike cron, it does not assume that the system is running continuously.
Every time Anacron is run, it reads a configuration file that specifies the jobs Anacron controls, and their periods in days. If a job wasn't executed in the last n days, where n is the period of that job, Anacron executes it. Anacron then records the date in a special timestamp file that it keeps for each job, so it can know when to run it again
apmd
The apmd package is a set of user-level programs to control the Advanced Power Management system found in all modern laptop computers and most modern desktops. apmd talks to the Linux kernel APM layer, which does all the hardware-dependent stuff.
atd
atd runs jobs queued by at.
autofs
Auto-autofs detects Disks, Partitions, CD-ROMs, Floppies etc. and sets up an automount configuration.
So it provides an easy access to the hardware.
Auto-autofs is a Perl script that searches the hardware for block devices using the /proc directory. It finds partitions on harddisks via fdisk and tries to detect the filesystems.
bcm5820
Hardware cryptographic accelerator support for Broadcom BCM5820 eCommerce Processor.
chargen
Character Generator Protocol.
A useful debugging and measurement tool is a character generator service. A character generator service simply sends data without regard to the input. Listens on port 19 TCP/UDP.
Details: http://www.networksorcery.com/enp/RFC/Rfc864.txt
chargen-udp
See chargen.
crond
Daemon to execute scheduled commands.
cups
The Common UNIX Printing System ("CUPS") is a cross-platform printing solution for all UNIX environments. It is based on the "Internet Printing Protocol" and provides complete printing services to most PostScript and raster printers.
cups-lpd
This is the CUPS Line Printer Daemon ("LPD") mini-server that supports legacy client systems that use the LPD protocol.
daytime The Daytime Protocol (Internet RFC 867) is a simple protocol that allows clients to retrieve the current date and time from a remote server. While useful at a bsic level, the Daytime protocol is most often used for debugging purposes rather than actually acquire the current date and time. The daytime protocol is available on TCP port 13.
daytime-udp
See daytime.
echo
Service for testing, everything you send to port 7 (echo) would be sent back to you.
echo-udp
see echo
gpm
General Purpose Mouse Daemon. Necessary only if you want to use your mouse on the console (not xterms).
httpd
The apache web server.
iptables
firewall
irda
(Infrared Data Association) is an industry standard for infrared wireless communication.
irqbalance
Daemon to balance irq's across multiple CPUs. Only useful on SMP systems (more than one processor)
isdn
ISDN (Integrated Services Digital Network). Use only with ISDN network interfaces.
ktalk
A graphical talk client for KDE.
kudzu
Detects and configures new and/or changed hardware on a system.
lisa
LISa is a small daemon which is intended to run on end user systems. It provides something like a "network neighborhood", but only relying on the TCP/IP protocol stack, no smb or whatever.
The information about the hosts in your "neighborhood" is provided via TCP port 7741.
To use it: from a client computer, open konqueror and type lan://targetIP
More information: http://lisa-home.sourceforge.net/
messagebus
D-BUS is first a library that provides one-to-one communication between any two applications; dbus-daemon-1 is an application that uses this library to implement a message bus daemon. Multiple programs connect to the message bus daemon and can exchange messages with one another.
More information: http://www.freedesktop.org/software/dbus/doc/dbus-daemon-1.1.html
microcode_ctl
It decodes and sends new microcode to the kernel driver to be uploaded to Intel IA32 processors. (Pentium Pro, PII, PIII, Pentium 4, Celeron, Xeon etc - all P6 and above, which does NOT include pentium classics)
It signals the kernel driver to release any buffers it may hold.
The microcode update is volatile and needs to be uploaded on each system boot i.e. it doesn't reflash your cpu permanently, reboot and it reverts back to the old microcode.
This driver is designed for Intel IA32 microprocessors only, it will not work with AMD or any other non-Intel processors as they don't support microcode updates or they support it in a manner different from Intel's specs.
More information: http://www.urbanmyth.org/microcode/?? http://microcodes.sourceforge.net/
mysqld
MySQL database server.
named
DNS server. Bind.
netfs
Network Filesystem Mounter. Needed for mounting NFS, SMB and NCP shares on boot.
network
Activates all network interfaces at boot time.
nfslock
To help manage file access conflicts and protect NFS sessions during failures, NFS offers a file and record locking service called the network lock manager. The network lock manager is a separate service NFS makes available to user applications. To use the locking service, applications must make calls to standard lock routines.
ntpd
The ntpd sets and maintains the system time of day in synchronism with Internet standard time servers. It is a complete implementation of the Network Time Protocol (NTP) version 4. Allows other computers to synchronize system time with your server.
pcmcia
PCMCIA cards.
portmap
The portmap service is a dynamic port assignment daemon for RPC services such as NIS and NFS.
postgresql
PostgreSQL database server.
random
Initialize kernel random number generator
rawdevices
Block devices.? Links hardware to devices that store data.
rhnsd
Red Hat Network Service. Informs you about official security and bug updates for your system.
rsync
Its just like rpc with much more features. Provides a very fast method for bringing remote files into sync.
saslauthd
SASL (Simple Authentication and Security Layer) authentication server. Server to allow others identify on this server.
sendmail
Mail server, allows to send emails using this machine as mail server.
services
An internal xinetd services, listing active services.
sgi_fam
File Alteration Monitor, provides an API that applications can use to be notified when specific files or directories are changed. For example, consider a graphical file manager, when the user removes a file thru the file manager, their changes are visible immediately.
smartd
Self Monitor Analysis and Reporting Technology System. Monitor you hard disk for failures.
smb
Samba, allows to share and access MS windows network.
snmpd
Simple Network Management protocol. A standard protocol for non-windows networks.
More information: http://www.ncsa.uiuc.edu/UserInfo/Resources/Hardware/IBMp690/IBM/usr/share/man/info/en_US/a_doc_lib/cmds/aixcmds5/snmpd.htm
snmptrapd
This is an SNMP application that recieves and logs SNMP TRAP and INFORM messages. Uses UDP port 162.
squid
Web proxy cache. http://www.squid-cache.org/
sshd
Secure Shell daemon, allows secure and remote logging to this machine.
syslog
Logs all system activities.
time
Retrieve the date and time from a host or hosts on the network and set the local system time TCP version.
time-udp
Retrieve the date and time from a host or hosts on the network and set the local system time UDP version.
tux
The TUX Web Server is an HTTP daemon for Linux . The TUX Web Server is different from other Web servers in that it runs partially from within the Linux kernel as a module, or kernel subsystem. Given sufficient networking cards, it enables direct scatter-gather direct memory access (DMA) and hardware-based TCP/IP checksums from the page cache (the Linux file data cache) directly to the network, avoiding extra data copies.
vncserver
VNC stands for Virtual Network Computing. It is remote control software which allows you to view and interact with one computer (the "server") using a simple program (the "viewer") on another computer anywhere on the Internet.
More? information: http://www.realvnc.com/
vsftpd
Secure FTP daemon.
More information: http://vsftpd.beasts.org/
winbind

Winbind is an nss switch module to map Windows NT Domain databases to Unix.
In combination with Samba and pam_ntdom, a Unix box will be able to integrate straight into a full Windows NT Domain environment, without needing a Unix Account database.
More information: http://www.samba.org/

xfs
The X font server (xfs) provides a standard mechanism for an X server to communicate with a font renderer, frequently running on a remote machine. It usually runs on TCP port 7100.
You need to be running xfs if you want a remote X terminal to be able to use fonts from your system, or if you want to use fonts that your X server doesn't understand (and the font server does).
xinetd
Service wrapper. xinetd is a replacement for inetd, the internet services daemon.
xinetd - eXtended InterNET services daemon - provides a good security against intrusion and reduces the risks of Denial of Services (DoS) attacks. Like the well known couple (inetd+tcpd), it enables the configuration of the access rights for a given machine.
More information: http://www.xinetd.org/
yum
yum is an automatic updater and package installer/remover for rpm systems.
It automatically computes dependencies and figures out what things should occur to install packages.
It makes it easier to maintain groups of machines without having to manually update each one using rpm.
More information: http://linux.duke.edu/projects/yum/

服務名稱
含義
acpid
配置文件:/proc/acpi/event
預設端口:無
說明:Advanced Configuration and Power Interface,為替代傳統的APM電源管理標準而推出的新型電源管理標準。
是否需要啟動:如果你需要對電源進行管理,那就需要啟動。
anacron
配置文件:/etc/anacron
預設端口:無
說明:一個自動化運行任務。Red Hat Linux 隨帶四個自動化任務的工具:cron、 anacron、at、和 batc。當你的Linux主機并不是全天候開機,這個anacron就可以幫你執行在“crontab”設定的時間內沒有執行的工作。舉例來說,當你的 主機在晚上12:00會自動關閉,但是偏偏crontab這個例行性工作是在4:00工作,這個時候例行性工作就不能起作用了。不過利用anacron就 能做到。
是否需要啟動:如果主機已經24小時開機,而且運行了cron,那么這個守護程序就不需要啟動了。
apmd
配置文件:/etc/sysconfig/apmd
預設端口:無
說明:Advanced Power Management,高級電源管理。傳統的電源管理標準。一般系統都會同時支持APM和APMD兩種標志,但系統加載時只需加載一個即可。對于筆記本電腦比較有用,可以了解系統的“電池電量”。
是否需要啟動:如果我們使用的是臺式電腦或一直開機的機型,就不需要使用這個守護程序。
atd
配置文件:/etc/at.allow,/etc/at.deny
預設端口:無
說明:一個自動化運行任務。
是否需要啟動:通常需要啟動。不過如果你一直使用cron,那么也可以不啟動。
autofs
配置文件:/etc/rc.d/init.d/autofs
預設端口:無
說明:實現光盤、軟盤的自動加載。
是否需要啟動:一般不需要啟動。
chargen
chargen-udp
預設端口:TCP/UDP 19
說明:Character Generator Protocol,一種網絡服務,主要功能是提供類似遠程打字的功能。
是否需要啟動:為安全起見,盡量關閉這個服務。
cpuspeed
說明:監測系統空閑百分比,降低或加快CPU時鐘速度和電壓從而在系統空閑時將能源消耗降為最小,而在系統繁忙時最大化加快系統執行速度。
更多細節:
是否需要啟動:需要啟動。
crond
配置文件:/etc/crontab
預設端口:無
說明:用來執行例行性命令的守護程序。
是否需要啟動:必須啟動。
cups
配置文件:
CUPS服務器配置文件:/etc/cups/cupsd.conf
CUPS客戶端配置文件:/etc/cups/client.conf
CUPS打印機配置文件:/etc/cups/printers.conf
CUPS中類(class)配置文件:/etc/cups/classes.conf
說明:Common UNIX Printing System,公共UNIX打印支持,為Linux提供打印功能。
是否需要啟動:如果不安裝打印機,就不需要啟動。
cups-lpd
預設端口:無
說明:CUPS Line Printer Daemon ("LPD"),提供打印功能。
是否需要啟動:如果不安裝打印機,就不需要啟動。
daytime
daytime-udp
預設端口:TCP 13
說明:Daytime協議(RFC867)是一個簡單的協議,為客戶機實現從遠程服務器獲取日期和時間的功能。
是否需要啟動:不用啟動。
echo
echo-udp
預設端口:7
說明:服務器回顯客戶數據服務。
是否需要啟動:不用啟動。
gpm
配置文件:/etc/sysconfig/mouse
預設端口:無
說明:General Purpose Mouse Daemon ,gpm為文本模式下的Linux程序如mc(Midnight Commander)提供了鼠標的支持。它也支持控制臺下鼠標 的拷貝,粘貼操作以及彈出式菜單。
是否需要啟動:沒必要的話,建議不要啟動。
iptables
說明:防火墻。
是否需要啟動:必須啟動。
irda
Infrared Data Association,是一個實現紅外無線數據傳輸的工業標準。
irqbalance
對多個系統處理器環境下的系統中斷請求進行負載平衡的守護程序。
是否需要啟動:如果你只安裝了一個CPU,就不需要加載這個守護程序。
isdn
Integrated Services Digital Network,綜合數字服務網絡。提供對isdn設備的支持。
kudzu
配置文件:
/etc/sysconfig/hwconf
/etc/sysconfig/kudzu
說明:硬件自動檢測 程序,會自動檢測硬件是否發生變動,并相應進行硬件的添加、刪除工作。當系統啟動時,kudzu會對當前的硬件進行檢測,并且和存儲在 /etc/sysconfig/hwconf中的硬件信息進行一一對照,如果某個硬件從系統中被添加或者刪除時,那么kudzu就會察覺到,并且通知用戶 是否進行相關配置,然后修改/etc/sysconfig/hwconf,使硬件資料與系統保持同步。如果/etc/sysconfig/hwconf這 個文件不存在,那么kudzu將會從/etc/modprobe.conf,/etc/sysconfig/network-scripts/和 /etc/X11/XF86Config中探測已經存在的硬件。
是否需要啟動:如果啟動kudzu,則每次啟動系統,都會檢查新硬件(checking new hardware),會延長系統啟動的時間。如果你不打算增加新硬件,那么就可以關閉這個啟動服務,以加快系統啟動時間。
mdmonitor
與RAID設備相關的守護程序。
mdmpd
與RAID設備相關的守護程序。
messagebus
D-BUS是一個庫,為兩個或兩個以上的應用程序提供一對一的通訊。
dbus-daemon-1是一個應用程序,它使用這個庫來實現messagebus守護程序。多個應用程序通過連接messagebus守護程序可以實現與其他程序交換信息。
更多細節:
microcode_ctl
可以編碼以及發送新的微代碼到kernel以更新Intel IA32系列處理器(Pentium Pro,PII,PIII,Pentium 4,Celeron, Xeon 等等 – 全部 P6 以及更高,不包括 pentium classics)。
更多細節:
netdump
News Backup Dump Server,遠程備份服務器。
netfs
Network Filesystem Mounter,安裝和卸載NFS、SAMBA和NCP網絡文件系統。
netplugd
配置文件:
/etc/netplug/netplugd.conf
/etc/netplug.d/netplug
說明:network cable hotplug management daemon,netplugd是一個守護程序,可以監控一個或多個網絡接口的狀態,當某些事件觸發時運行一個外部腳本程序。
network
在系統啟動時激活所有的網絡接口。
nfs
網絡文件系統。
nfslock
NFS是一個流行的通過TCP/IP網絡共享文件的協議,此服務提供了NFS文件鎖定功能。
ntpd
配置文件:/etc/ntp.conf
說明:Network time Protocol daemon,網絡時間校正協議。簡單的說,NTP是用來使系統和一個精確的時間源保持時間同步的協議。
推薦大家看一篇文章:《NTP-讓網絡里的電腦時間精確到毫秒》
發表在2004年12月份的《在線技術》雜志第63頁
pcmcia
Pcmcia卡,支持筆記本電腦的PCMCIA 設備,如調制解調器, 網絡適配器, SCSI卡等等。
portmap
Portmap守護程序為RPC服務,如NIS和NFS提供動態端口的分配。
psacct
包括幾個工具用來監控進程活動的工具,包括ac,lastcomm, accton 和sa。
random
說明:快速的將系統的狀態在隨機的時間內存到景象檔案中,對于系統相當重要。因為在開機之后,系統會迅速的恢復到開機之前的狀態。
是否需要啟動:必須啟動。
rawdevices
在使用集群文件系統時用于加載raw設備的守護程序。
readahead
readahead_early
配置文件:/etc/readahead.early.files? /etc/readahead.files
說明:readahead和readahead_early是在Fedora core 2中最新推出的兩個后臺運行的守護程序。其作用是在啟動系統期間,將啟動系統所要用到的文件首先讀取到內存中,然后在內存中進行執行,以加快系統的啟動速 度。而上面兩個配置文件就保存著將要讀取到內存的文件列表。
rhnsd
Red Hat 網絡服務。通知你有關官方的安全信息以及為你的系統打補丁。
rpcgssd
rpcidmapd
rpcsrcgssd
說明:gestion NFS v4,是Linux 2.6內核新添的功能。
是否需要啟動:不需要啟動。
rsync
remote sync,遠程數據備份工具。
saslauthd
使用SASL的認證守護程序。
sendmail
郵件服務器。
services
一個內部xinetd服務,用于監聽活動的服務。
sgi-fam
實現實時數據鏡像。監控文件的變更,提供一個應用程序API接口用來當指定的文件火目錄改變時及時通知。
smartd
Self Monitor Analysis and Reporting Technology System,監控你的硬盤是否出現故障。
sshd
配置文件:
OpenSSH服務器配置文件:/etc/ssh/sshd_config
OpenSSH客戶端配置文件:/etc/ssh/ssh_config
預設端口:22
說明:Secure Shell Protocol,實現安全地遠程登陸管理主機。
是否需要啟動:如果想實現遠程管理,就需要啟動。
syslog
配置文件:/etc/syslog.conf
說明:記錄所有的系統行為。
是否需要啟動:必須啟動。
time
從遠程主機獲取時間和日期,采用TCP協議。
time-udp
從遠程主機獲取時間和日期,采用UDP協議。
vncserver
VNC (Virtual Network Computing,虛擬網絡計算),它提供了一種在本地系統上顯示遠程計算機整個“桌面”的輕量型協議。
xfs
預設端口:TCP 7100
說明:x font server,X Window字型服務器,為本地和遠程X服務器提供字型集。
是否需要啟動:如果使用run-level為5的圖形界面,那么就需要啟動。
xinetd
配置文件:/etc/xinetd.conf
說明:xinetd作為inetd的后續版本,負責管理系統中不頻繁使用的服務,這些服務程序在有請求時才由xinetd服務負責啟動運行,一 旦完成服務請求服務程序結束運行,這樣可以有效地減少對系統資源的占用率。通常,xinetd管理的程序有telnet、ftp、rsh和rlogin。 關閉inetd也就關閉了這些由它管理的服務。
更多細節:http://www.xinetd.org/
是否需要啟動:必須啟動。
yum
配置文件:/etc/yum.conf
說明:Yellow Dog UpdaterModified,是一個自動更新、安裝和刪除RPM軟件包的管理程序,它會自動計算軟件包的管理程序,并判斷哪些軟件應該安裝,哪些軟件則不必安裝。
是否需要啟動:以系統管理策略而決定是否啟動