Chapter 31: Daemons

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Chapter 31 Daemons

• CS-691x UNIX Administration
• Presented By Dan Winter Date
  07/01/1999

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Essential Daemons

• init the first process that runs (PID 1)
• cron the general system scheduler
• inetd the super-daemon--master

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Essential Daemons init

• Two startup modes
• child shell
• single shell
• linux single, init 1
• /etc/inittab
• Errors -gt /var/logs/messags, console
• Killing off Zombie Processes

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Essential Daemons cron

• Runs commands at preset times
• Daily cleanup, Filesystem management
• /etc/crontab
• /etc/cron.daily, /etc/cron.hourly,
  /etc/cron.monthly, /etc/cron.weekly

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Essential Daemons inetd

• /etc/inetd.conf
• /etc/services
• /etc/rpc
• /etc/rc.d/init.d

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Inetd /etc/inetd.conf

• name socket protocol fork
  executor full-qualified pathshell
  stream tcp nowait root
  /usr/sbin/tcpd in.rshdlogin stream
  tcp nowait root /usr/sbin/tcpd
  in.rlogindexec stream tcp nowait
  root /usr/sbin/tcpd in.rexecdtalk
  dgram udp wait root
  /usr/sbin/tcpd in.talkdntalk dgram
  udp wait root /usr/sbin/tcpd
  in.ntalkddtalk stream tcp waut
  nobody /usr/sbin/tcpd in.dtalkd

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Inetd /etc/services

• name port/type alias
  comment biff 512/udp
  comsat login 513/tcp
  BSD rlogind(8) who
  513/udp whod BSD rwhod(8)
  shell 514/tcp cmd
  BSD rshd(8) syslog 514/udp
  BSD syslogd(8) printer
  515/tcp spooler BSD
  lpd(8)

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Inetd /etc/rpc

• name port aliases
  portmapper 100000 portmap sunrpc
  rstatd 100001 rstat rstat_svc
  rup perfmeter rusersd 100002
  rusers nfs 100003
  nfsprog

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Inetd /etc/rc.d/init.d

• ls /etc/rc.d/init.d amd.init inet
  network sendmail.init
  yppasswd.initcron.init keytable
  nfs single
  ypserv.initfunctions killall
  nfsfs skeletongpm
  lpd.init pcmcia smbhalt
  mars_nwe.init portmap.init
  snmpd.inithttpd.init named.init
  random syslog
• /etc/rc.d/init.d/inetUsage inet startstop

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NFS/NIS

• NFS (Already covered)
• /etc/exports, /etc/fstab,
  /etc/rc.d/init.d/nfs, /etc/rc.d/init.d/nfsfs
• NIS (Separate Topic)
• /etc/ypserv.conf, /usr/sbin/ypserv,
  /usr/sbin/yppoll, /usr/sbin/yppush,
  /usr/sbin/ypset, /usr/bin/ypcat,
  /usr/bin/ypmatch, /usr/bin/ypwhich,
  /usr/bin/yppasswd, etc.

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Internet

• talkd, rwhod, ftpd, popper, rlogind, telnetd,
  rshd, rexecd, timex, xntpd, routed, gated, named,
  nntpd, syslogd, fingerd, httpd, and more...

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Internet talkd

• /etc/inetd.conf
• talk dgram udp wait root
  /usr/sbin/tcpd in.talkd
• ntalk dgram udp wait root
  /usr/sbin/tcpd in.ntalkd
• dtalk stream tcp waut nobody
  /usr/sbin/tcpd in.dtalkd
• /etc/services
• talk 517/udp
  BSD talkd(8)
• ntalk 518/udp
  SunOS talkd(8)
• /usr/sbin/inetd, (/usr/sbin/talkd)
• /usr/bin/talk, /usr/bin/mesg

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Internet ftpd

• /etc/inetd.conf
• ftp stream tcp nowait root
  /usr/sbin/tcpd in.ftpd -l -a
• tftp dgram udp wait root
  /usr/sbin/tcpd in.tftpd
• /etc/services
• ftp-data 20/tcp
• ftp 21/tcp
• tftp 69/udp
• sftp 115/tcp
• /usr/sbin/inetd
• /usr/bin/ftp, /usr/bin/tftp, /usr/bin/ncftp,
  /usr/bin/pftp

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Internet rlogind, telnetd, rshd, rexecd

• /etc/hosts.equiv
• ssu037.ssu.edu
• listserver.ssu.edu
• /.rhosts
• ssu037.ssu.edu dkwinter
• listserver.ssu.edu dkwinter
• /usr/sbin/inetd
• /bin/rlogin, /bin/rsh, /bin/rcp, /bin/rexec,
  /bin/telnet

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Internet routed, gated

• /etc/gateways Used for definition of distant
  gateways
• /etc/networks Associations of IP numbers with
  network names
• /etc/hosts Internet host table
• netstat -nr
• Kernel IP routing table
• Destination Gateway Genmask
  Flags MSS Window irtt Iface
• 131.118.32.0 0.0.0.0 255.255.240.0
  U 1500 0 0 eth0
• 127.0.0.0 0.0.0.0 255.0.0.0
  U 3584 0 0 lo
• 0.0.0.0 131.118.47.254 0.0.0.0
  UG 1500 0 0 eth0
• /usr/sbin/routed, /usr/sbin/gated
• /bin/netstat, /sbin/ifconfig, /sbin/route,
  (/etc/defaultrouter)

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Internet named

• /usr/local/adm/named DNS database for a
  Zone-capable server
• /etc/resolv.conf Search domain, and nameservers
  listed by priority
• /etc/hosts Internet host table
• nslookup psu.edu
• Server ssu037.ssu.edu
• Address 131.118.32.11
• Name psu.edu
• Addresses 146.186.149.198, 146.186.157.8,
  146.186.15.17
• /usr/sbin/named
• /etc/resolv.conf, /usr/bin/nslookup, /usr/bin/dig

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Internet syslogd

• /etc/syslog.conf
• Log anything (except mail) of level info or
  higher.
• Don't log private authentication messages!
• .infomail.noneauthpriv.none
  /var/log/messages
• /usr/sbin/syslogd
• /etc/syslog.conf, /var/log/

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Internet httpd

• /usr/local/etc/httpd/httpd.conf Used for
  definition of web server
• /usr/local/etc/httpd/access.conf Used for
  definition of directories
• /usr/local/etc/httpd/srm.conf Used for
  definition of web settings
• /usr/sbin/httpd

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