cron-log

RH133

Red Hat Enterprise Linux System Administration

Welcome!

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Objectives

Printing and Administration Tools Understanding Printer Installing and Managing Printer Server and Client Using Scheduling [ cron ] System Logging

X Windows System Understanding Server and Client Managing X Server Using Remote Desktop Configuration Utilities

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Printing and Administration Tools

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Understanding Printer

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Printer TERMSPrinter TERMS Printer Print Device Print Driver Print Server Print Client Network Printer Local Printer Print Queue Print Job

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Common UNIX Printing Service [ CUPS ]

CUPS, the common printing system, is the primary printing system under Red Hat Enterprise Linux. CUPS supports a new Internet Printing Protocol, IPP, based on HTTP.

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Installing and Managing Printer Server and Client

CUPS Configuration Files

/etc/cups/cupsd.conf/etc/cups/cupsd.conf cupsd server configuration file

/etc/cups/printers.conf/etc/cups/printers.conf Print queue configuration file

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Printing Commands system-config-printersystem-config-printer : Utility to install and manage print devices lprlpr : command to send print jobs to print device lpqlpq : command to view print queues lprmlprm : command to remove print jobs lpadminlpadmin : command line tool for printer administration

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Using Scheduling [ cron ]

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cron Used to schedule recurring events Use crontab to edit, install and view job schedules Command Examples Crontab OPTIONS

-l -l list crontablist crontab -r-r removes crontabremoves crontab -e-e edits crontabedits crontab

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Using Crontab File

• Fields in a crontab file can be separated by any number of tabs or spaces

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Controlling Cron

Restrict / allow user access to cron /etc/cron.allow/etc/cron.allow /etc/cron.deny/etc/cron.deny

Contains usernames to allow / deny access

Disable “email” notifications:

If email notification is not required then put the following command at the end

of the cron job line:

>/dev/null 2>&1

Crontab “LOG FILE” generation:

30 18 * * * somecommand > /somelocation/logfilename.log

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System Logging

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What is System Logging ?

An important part of maintaining a secure system is keeping track of the activities that take place on the system. If you know what usually happens, such as understanding when users log into your system, you can use log files to spot unusual activity

Two main logging daemonsTwo main logging daemons

klogdklogd :The kernel log daemon service logs kernel messages

and events

syslogdsyslogd :The syslog daemon logs all other process activity. You

can use the log files that syslogd generates to track activities on your

system

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Log Files /var/log/dmesg/var/log/dmesg : Kernel log messages /var/log/messages/var/log/messages : Standard system error messages /var/log/maillog/var/log/maillog : Mail System messages /var/log/secure/var/log/secure : Security, authentication, and xinetd messages

utmpdump /var/log/wtmp

used for monitoring login activity.

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Configuring Central Log Server Server Side – Allow “syslogd” to accept remote message

vi /etc/sysconfig/syslog SYSLOGD_OPTIONS=”-r -m 0”

Restart the “syslogd” service syslog restart

Client Side – Instruct client to send log to Central Server

vi /etc/syslog.conf user.* @192.168.0.253

Restart “syslogd” service syslog restart

Test – On client

logger -i -t username “this is to be sent to remote server”

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X Windows System

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What is X Windows

The X Windows System is the foundation of the Linux graphical user interface (GUI). The X Windows System is maintained by X Consortium at http://www.X.org

The X Window System is designed as a flexible and powerful

client/server-based system

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Methods to establish X environment Two methods to establish the environment /usr/X11R6/bin/xinit/usr/X11R6/bin/xinit /usr/X11R6/bin/startx/usr/X11R6/bin/startx

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Configuration Utilities system-config-displaysystem-config-display mouseconfigmouseconfig switchdeskswitchdesk

?Questions