Important Daemons and Startup Services

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.