Linux Services the complete list

List of Linux services/daemons that you can use, with Description and whether it is mandatory or not, and with explanation

Alphabetical Listing of Services
Service Name	Required [Yes/No]	Description	Comments
acon	No	Language support	Specifically for the right to left written languages: Arabic, Farsi and Hebrew
acpi	No	Power Management	laptop battery fan monitor
acpid	No	Listening daemon	This listens for and dispatches acpi events from the kernel
adsl	No	Internal ADSL switch control	Use this only if you have an internal adsl switch for your internet connection.
alsa	No	Advanced Linux Sound Architecture	The only sound system actually included in the kernel
anacron	No	Periodic Command Scheduler	a task scheduling tool
apmd	No	Power Management	Laptop power management
apmiser	No	Power Management	Yet another laptop battery extender
arpwatch	No	Ethernet ip address pairing monitor	monitors and logs remote ip addresses with hostnames.
atd	No	Periodic Command Scheduler	a task scheduling tool
autofs	No	Automount services	one of the several automounting of file systems on demand services. Some of which are distro specific, if the distro you are using has its own automount system, do not use this one.
bluetooth	No	The core of Bluetooth	For all Bluetooth services.
bootparamd	No	boot server	old means for booting diskless clients / thin clients, the newer method is the zeroconf system.
canna	No	Japanese conversion engine
capi4linux	No	Basic CAPI subsystem
cpqarrayd	No	Hardware Service	Compaq Raid Array Monitor
cpufreq	No	Hardware Service	Probes and configured CPU frequency daemon modules
cpufreqd	No	Hardware Service	This one will automatically scale cpu frequency to reduce overheating. Should be useful for over-clocking.
crond	Yes	Periodic Command Scheduler	THE task scheduling tool.
cups-lpd	No	Enables older Linux and commercial Unix systems to connect to cups server	Useful only if you have to allow older systems access to the printers
cups	Yes	Common Unix Printing System	A must have to enable printing
cvs	No	Concurrent Versioning system	For managing multi user documents.
devfsd	No	System Maintenance	This service only cleans up dynamic desktop directories; it is not needed unless your system crashes often.
dhcpd	No	The DHCP server	Is your network large enough that static IPs are a pain, then this will make it easier, giving you DHCP IP configuration for your network.
diald	No	Smart auto dialer for dialup networking	This service will connect to the network on demand, as in you type an email and hit send, it will connect you, send the email and disconnect you.
dkms	No	Autoinstall Boot for DKMS	Distro specific tool, for OEM style installations. This allows for a first boot setting of root password and user name password for regular use. the final configuration of the system.
dm	Yes	Display Manager	The core of the x-server, required for using any GUI.
dnbc	No	Digital Network Bind Chrooter	This is a simple bash script that puts a BIND server in a chroot jail. Install BIND, launch the script, and restart named
drakxtools_http	No	Miniserve administration server	Distro specific tool for remote system administration
dund	No	Bluetooth Dialup networking
fam	No	File system Alteration Monitor	Logger for all changes to a file system.
finger	No	Remote access of data.	This server will allow remote access of user login data, last login date and time. useful for monitoring employee work habits when you are not in the office, major breach of security, in that you are effectively publishing confidential company data online
freshclam	Yes	ClamAV updater	Automatic updates for ClamAV
gpm	Yes	Mouse	Console mode mouse driver
haldaemon	No	Hardware Monitoring System	This monitors for hardware changes, will alter you to new or altered hardware.
harddrake	No	Hardware Service	Distro specific hardware detection and configuration
heartbeat	No	High Availability services	This is intended to increase the priority of critical servers and services
hidd	No	Bluetooth H.I.D. Server
hplip	No	HP Linux Printing and Imaging	Older version of HP supplied drivers for their all in one products
hpoj	No	Pital?init, HP office jet printer drivers	Older drivers for HP office jet, newer drivers are included with cups drivers for the printers
httpd	No	Apache Web server	There are two reasons for this to be on a system, one is it is to be used as a Web server, the other it will be a Web site development machine. If neither is true, do not install Apache and this won't be here.
hylafax?server	No	Enterprise Fax?modem service	This works for class 1 and class 2 fax modems only. This must be running if you intend to use hylafax to send a fax through the modem. This is not the only fax tool available.
ibod	No	ISDN MPPP bandwidth on demand	Useful with dialup networking, this will connect as needed to the network.
identd	No	Identification through TCP connection
imaps	No	secure IMAP server
imaps	No	IMAP server
iplog	No	Logs TCP, UDP, ICMP connections with hostname of remote host	Useful network monitoring tool.
ipop2	No	POP2 mail server
ipop3	No	POP3 mail server
ipsec	No	Encrypted and Authenticated communications	KLIPS is the kernel half, PLUTO is the user space half. very useful for remote access situations
iptables	Yes	kernel based Packet Filtering firewall	All good Linux firewalls are based on this service.
ipvsadmin	No	Linux Kernel IP virtual server	This is one of the oldest networking systems in Linux, not used very much any more.
irda	No	Infra Red Device Interface	Older wireless device support
keytable	Yes	keyboard map	This tells the system exactly which keyboard you are using.
kheader	No	Boot Services	This automatically regenerates the kernel header in /boot
lads	No	Login Anomaly Detection System	A tool to track login attempts and warn of attempted intrusion.
laptop?mode	No	Power Management	A tool to reduce power consumption, extending the life of the laptop battery
leafnode	No	NNTP service for X?INETD
lisa	No	LAN information server
lmsensors	No	Hardware health monitor	This requires that the mainboard of the system supports and has monitoring systems in place, such as the CPU temperature and voltage monitors.
mailman	No	GNU Mailing List Manager	A commonly used mailing list tool, with a Web interface for administration, written in Python. It allows list members to communicate by sending an email to one address, and replying to the same address. Can also be used to send out newsletters / product updates to those that requested such
mandi	No	Interactive Firewall	Special service to allow for temporary wireless access to the system, will open the iptables firewall for current session only access for wireless devices, on user approval only, not automatically.
mdadm	No	Monitoring Service for software raid	This also is a management tools for said software raid volumes.
mdnsresponder	No	Zeroconf DNS configuration tool
messagebus	Yes	Event monitoring service	This one sends broadcast messages to all users when needed, like the server is going down for reboot.
mon	Yes	System Monitoring daemon	A lot of system services require this in order to function
mysqld	No	MySQL server	If you don't need this database, why turn it on?
named	No	BIND server	yes, the infamous name server.
netplugd	No	Network Card daemon	This service monitors the network interface, turning it off or on depending on signal, used mainly for laptops that may not always be connected.
network	Yes	Networking	This turns the network card on, or powers the modem.
nfs	No	Network File Share	This enables the clients to access NFS shares, it is required for the client machines in an NFS system.
nfsfs	No	The Network File Share Server	This should only be active on the network server
nfslock	No	NFS file locking	This should only be active if you are using NFS networking / file share functionality.
nifd	No	Howl Client	This provides ipv4 link?local services for zeroconf networks / systems
nscd	No	Password and group lookup service	This works for slow protocols like N.I.S/Y.P. nist, ldap and hesiod. It is designed to have a longer timeout specifically for these protocols
ntpd	No	Version 4 of the NTP server
numlock	No	number lock light control	This will keep the Numlock activated, turning the keyboard number pad on.
oki4daemon	No	compatibility daemon for OKI4 and compatible winprinters	only useful if you have one of these printers
pand	No	Bluetooth Personal Area Networking	For home area Bluetooth based networking.
partmon	Yes	Partition Monitoring	This service keeps track on free space on mounted partitions. used by most file system browsers for calculating free space on a given partition.
pcmcia	No	Personal Computer Memory Card International Association
pg_autovacum	No	PostgreSQL maintenance	This will automatically run the vacuum needed by PostgreSQL to reduce disk space, pulling temp tables from the db as well as deleting temp files created by PostgreSQL.
pop3s	No	Secure POP3 server	SSL enabled POP3 server
portmap	No	RPC support	Support for those rare apps that use rpc.
Postgresql	No	The Postgresql Database Engine	You only need this if you are either running a postgresql db drives application or are developing one.
postfix	No	email server	asendmail compatible email server, newer than sendmail itself, becoming more commonly used than sendmail.
pptp	No	Shutdown service for ppp	A clean shutdown service for PPP tunnels, used when on ups to avoid lock file problems when power returns to the system.
prelude	No	IDS	Intrusion Detection system
psacct	No	Process Accounting	A Tracker of active processes, a waste of resources really
rawdevices	Yes	Assigns rawdevices to blocks for use	This is needed for DVDS, and oracle DBMS among other things
rsync	No	Remote Synchronization	A server to enable remote synchronization of files in a specified directory tree. Commonly used for maintaining mirror sites, can also be used to keep company files current for backup purposes.
saned	No	Network Scanner Service	To provide access to your scanner from any workstation in the network.
shorwall	Yes	Firewall	A very good IPTables based firewall.
smartd	No	Self Monitor Service	For OS access to smart enabled devices, this will allow Linux to tell you if the device is starting to go bad, but relies on the device smart feature for accuracy.
smb	No	Samba Network Services	This provides the samba services to enable Windows network compatibility.
snmpd	No	Simple Network management Protocol	For use in a small [ home office ] network
sound	No	Sound System	This is the core of the Linux sound system, nice for desktops, a waste of resources on a server
squid	No	Caching Tool	Used to cache Web pages and DNS entries
ssh?xinetd	No	OpenSSH server for x?inetd	a run on demand version of OpenSSH
sshd	No	OpenSSH server	Only turn this on if you require SSH access to your system, and are not going to use the x?inetd version.
subversion	No	Concurrent Versioning system	New alternative to CVS
swat	No	Samba Web Administration Tool	Web based Samba administration
syslog	Yes	System Logging	A Required service, it controls all logging on the entire system.
tmdns	No	Multicast dns responder	For use in zeroconf environments
ultrabayed	No	ThinkPad tool	This detects the presence of the ultrabay for your IBM ThinkPad and starts / stops the IDE interface as appropriate.
upsd	No	NUT daemon and drivers	An uninterrupted power supply monitoring and reporting tool. This tool reports to a central site to generate a database on ups statistics.
upsmon	No	Monitoring tool for UPS	This will monitor the status of the ups, and shut the system down when it's running low.
vncserver	No	Server for Virtual network computing	Very useful for using VNC in projects.
Webmin	No	Remote Administration tool	Distro Agnostic Remote administration tool. Useful for when the machine will not be physically accessible at all times; such as Web server farm.
winbind	No	Samba Name Server	Required for samba networking to function. This maps user and group data from the windows network to the Linux workstation
wine	No	Wine Is Not an Emulator	This enables running MS Windows executables in Linux. WINE is a limited version of the commercial product Crossover Office.
wlan	No	Control Daemon	This Controls services, it is not commonly used as the services are generally controlled through the init process.
x?inetd	Yes	Server for monitoring and controlling other servers	This is required service, and it actually reduces CPU load on a server. if you need SSH, ftp, etc but not all the time, the x?inetd version will start them on request, even remote request. This allows for them to be available, but frees the clock?cycles if they are only being used a few times a day / week.
xfs	Yes	X Font Server	If you are going to be running a GUI at any point in time, this will be required.
ypbind	No	Name Server for Sun's YP server	This is for GLIBC based NIS / YP networked systems.