RH033 Unit17 Essential System Administration Tools
Objectives
Upon completion of this unit, you should be able to:
- Explain the process of installing Red Hat Enterprise Linux
- Indentify services, their status and be able to manage the runlevels which start and stop them
- Install software using multiple installation methods
- Understand the basic principles of Red Hat Enterprise Linux security, firewalls and SELinux
Planning an Installation
1) What hardware does the system use?
- Check the hardware compatibility
2) Read the release-notes file on the first CD or at [url]http://www.redhat.com[/url]
- Provides valuable summary of features and gotchas
Performing an Installation
1) Installer can be started from:
- CD-ROM or DVD-ROM
- Use Device
- Network (PXE)
2) Supported installation sources:
- Network Server (ftp, http or nfs)
- CD-ROM or DVD-ROM
- Hard Disk
Managing Services
1) What is a service?
2) Graphical Interface to Service Management: system-config-services
3) Command Line interface to service management
- service
- chkconfig
Managing Software
1) Software is provided as RPM packages
- Easy installation and removal
- Software information stored in a local database
2) Packages are provided by Red Hat Network
- Centralized management of multiple systems
- Easy retrieval of errata packages
- Systems must be registered first
- Custom package repositories may also be used
The Yum Package Management Tool
1) Front-end to rpm, replacing up2date
2) Configuration in /etc/yum.conf and /etc/yum.repos.d/
3) Used to install, remove and list software
- yum install packagename
- yum remove packagename
- yum update packagename
- yum list available
- yum list installed
Graphical Package Management
1) pup
- Application->System Tools->Software Updater
- List and install software updates
2) pirut
- Application->Add/Remove software
- View, install and un-install other packages
Securing the System
1) Basic security principles
- Avoid running services that you do not need
- Limit access to services that are running
- Avoid using services that send data unencryped over the network such as instant message, pop, impa, and telnet
SELinux
1) Kernel-level security system
2) All processes and files have a context
3) SELinux Policy dictates how processes and files may interact based on context
- Policy rules cannot be overridden
- Default policy does not apply to all services
Managing SELinux
1) SELinux errors are logged in the System Log
2) SELinux can be disabled in an emergency
3) Disabling SELinux is discouraged!
4) System->Administration->Security Level and Firewall, SELinux tab
Packert Filtering
1) Network traffic is divided into packets
2) Each packet has source/destination data
3) Firewalls selectively block packets
Firewall and SELinux Configuration system-config-securitylevel
1) System->Administration->Security Level and Firewall
- Selectively allow incoming connections by port
- Specify interfaces to trust al traffic from
- Responses to outbound queries always accepted
2) More advanced configuration possible with other tools
End of Unit17
1) Questions and Answers
2) Summary
- System Installation Process
- Managing Services
- Software Installation Tools
- System Security