Important Daemons and Startup Services
These are programs or processes which are run at boot time. Some remain in
memory to execute various tasks when required (daemons). Most are started and
stopped with scripts in the /etc/rc.d/init.d directory (see above). The exact
contents of this directory will depend on which packages from a particular
distribution are installed. For example, installing the Apache package will
cause an httpd script to be placed in /etc/rc.d/init.d.
There are man pages on most of these. The Red Hat program tksysv (ntsysv is
the non graphical version) allows root to automatically configure which of
these are started automatically at boot time. The linuxconf program does the
same thing, although I haven't tried it. The utility chkconfig is also
designed to query and configure runtime services for different runlevels. The
www.mandrakeuser.org site has a good page on common services/daemons,
especially those included in recent versions of the Mandrake distribution.
A good source of information on daemons and services is the ``Linux Devices,
Daemons, Services'' chapter of the CTDP (2000a) document.
- amd - runs the automount daemon for remote filesystem mounting such as
nfs
- anacron - checks delayed `cron' tasks (see below) at boot time and
executes them. Useful if you have cron jobs scheduled but don't run your
machine all the time.
- apmd - Advanced Power Management BIOS daemon. For use on machines,
especially laptops, that support apm. Monitors battery status and can shut
down the system if power is too low.
- arpwatch - keeps watch for ethernet IP address pairings that are
resolved using the ARP protocol.
- atd - runs jobs queued by `at'
- autofs - control the operation of automount daemons, used to mount and
unmount devices on demand
- bootparamd - allows computers to boot from a Linux machine using the
BOOTP network protocol. A server process that provides information to
diskless clients necessary for booting
- crond - automatic task scheduler. Manages the execution of tasks that
are executed at regular but infrequent intervals, such as rotating log
files, cleaning up /tmp directories, etc.
- cups - daemon for print services under the Common Unix Printer System,
a replacement for lpd
- dhcpd - implements the Dynamic Host Configuration Protocol (DHCP) and
the Internet Bootstrap Protocol (BOOTP). Used to lease out IP addresses to
remote machines.
- drakfont - font server in Mandrake
- fetchmail - daemon to fetch mail at regular intervals from mail servers
- ftpd - ftp server daemon
- gated - routing daemon that handles multiple routing protocols and
replaces routed and egpup
- gpm - useful mouse server for applications running on the Linux
console.
- httpd - the Apache webserver hypertext transfer protocol daemon
- identd - The identd server provides a means to determine the identity
of a user of a particular TCP connection. Given a TCP port number pair, it
returns a character string which identifies the owner of that connection on
the server's system.
- inetd - listens for service requests on network connections,
particularly dial-in services. This daemon can automatically load and
unload other daemons (ftpd, telnetd, etc.), thereby economizing on system
resources. In the latest version of Red Hat (7.0 at the time of writing), it
has been replaced by xinetd. A partial list of services controlled by inetd
is listed below. Under many distributions, inetd will execute scripts in the
file /etc/inetd.conf.
- innd - Usenet news server daemon
- ipchains - daemon for packet forwarding. Used for configuring a
gateway/firewall.
- isdn provides ISDN network interfacing services
- isdn4linux - for users of ISDN cards
- kerneld - automatically loads and unloads kernel modules
- keytable - loads the appropriate keyboard map from /etc/sysconfig/
keyboard
- kheader -
- kudzu - detects and configures new or changed hardware during boot
- linuxconf - ``startup hook'' needed for the linuxconf system
configuration tool
- lpd - line printer and print spooler daemon
- mcserv - server program for the Midnight Commander networking file
system. It provides access to the host file system to clients running the
Midnight file system (currently, only the Midnight Commander file manager).
If the program is run as root the program will try to get a reserved port
otherwise it will use 9876 as the port. If the system has a portmapper
running, then the port will be registered with the portmapper and thus
clients will automatically connect to the right port. If the system does not
have a portmapper, then a port should be manually specified with the -p
option (see below).
- mysql - database server daemon
- named - provides DNS services
- netfs - network filesystem mounter. Used for mounting nfs, smb and ncp
shares on boot.
- network -activates all network interfaces at boot time by calling
scripts in /etc/sysconfig/network-scripts
- nfsd - used for exporting nfs shares when requested by remote systems
- nfslock - starts and stops nfs file locking service
- numlock - locks numlock key at init runlevel change
- pcmcia - generic services for pcmcia cards in laptops
- portmap - needed for Remote Procedure Calls
- postfix - mail transport agent which is a replacement for sendmail.
Now the default on desktop installations of Mandrake.
- postgresql - database server daemon
- random - random number generating daemon, related to security and
encryption
- routed - manages routing tables
- rstatd - kernel statistics server. Allows users on a network to get
performance statistics for any connected machine.
- rusersd - provides services that allow users to find one another over
the network
- rwalld - allows users to use rwall to write messages on remote
terminals
- rwhod - server which maintains the database used by the rwho(1) and
ruptime(1) programs. Its operation is predicated on the ability to broadcast
messages on a network.
- sendmail - mail transfer agent. This is the agent that comes with Red
Hat. Others, such as smtpd, are not included.
- smb - needed for running SAMBA
- snmpd - provides Simple Network Management Protocol support
- sound - daemon for managing sound
- squid - web page proxy server daemon
- syslogd - manages system log files
- smtpd - Simple Mail Transfer Protocol, designed for the exchange of
electronic mail messages. Several daemons that support SMTP are available,
including sendmail, smtpd, rsmtpd, qmail, zmail, etc.
- tcpd - from the tcp_wrappers package. Intercepts requests normally
handled by inetd and filters them through the files hosts.allow and
hosts.deny files, which can restrict access to services based on type of
service, origin of request, destination, etc. Requests are intercepted
because calls to particular services are replaced with calls to tcpd in
/etc/inetd.conf.
- telnetd - telnet server daemon
- usb - daemon for devices on Universal Serial Bus
- xfs - X font server
- xinetd - more modern replacement for inetd. It apparently allows for
similar kinds of access filters to the ones used by tcpd in conjunction with
inetd. xinetd replaces inetd as the default network services daemon in Red
Hat 7.0.
- xntpd - Network Time Protocol daemon. Provides a means to syncronize
time over the network.
- webmin - daemon for webmin web-based system administration program
- ypbind - NIS binder. Needed if computer is part of Network Information
Service domain.
