Lesson 1

This course expands on basic UNIX system administration by covering the fundamentals of UNIX network administration.
Furthermore, the course focuses on

1. TCP/IP networking under UNIX,
2. network monitoring, and
3. debugging.

The course also covers the variations between the Solaris, Linux, AIX, and HP-UX operating systems. The examples and exercises, however, focus on using a Linux or a Solaris system. In cases where the commands or procedures vary significantly between Linux and Solaris, two versions of examples and exercises are offered.One course is for Linux and the other for Solaris.

A Linux Administrator should have a strong understanding of the following Core Concepts:

1. User and Group Management: This includes creating and managing user accounts and groups, as well as understanding file permissions and access control lists (ACLs).
2. Disk and File System Management: This involves understanding the Linux file system hierarchy, disk partitions, mounting and unmounting storage devices, managing file system quotas, and working with file permissions.
3. Package Management: This includes installing, updating, and removing packages, as well as managing package repositories.
4. Command Line Interface (CLI): A Linux Administrator should be proficient in navigating the file system, managing files and directories, working with permissions and ownership, and using essential command line utilities.
5. System Monitoring and Performance Tuning: This includes monitoring system performance and resource usage, working with system logs, implementing log rotation and retention policies, and analyzing log files for troubleshooting and security auditing.
6. Security: This includes understanding the role of firewalls, intrusion detection systems, and the principle of least privilege. It also involves configuring and managing security services like SSH and implementing and managing access control policies.
7. Scripting and Automation: This involves the ability to write and maintain scripts in languages like Bash, Python, or Perl to automate tasks, customize solutions, and troubleshoot effectively.
8. Networking: A Linux Administrator should have a solid understanding of network configuration, troubleshooting, and the ability to work with network services like DNS and DHCP.
9. Backup and Recovery: This includes understanding the importance of regular backups, implementing and managing backup strategies, and being able to perform disaster recovery if needed.
10. Kernel and System Updates: This involves understanding how to update the Linux kernel, apply system updates, and manage system patches to keep the system secure and up-to-date.

These core concepts provide a solid foundation for a Linux Administrator to effectively manage and maintain Linux systems.

After completing the course, you will be able to:

1. Describe in general terms the different layers in the TCP/IP protocol
2. Understand the rules governing IP address classes and netmasks
3. Configure the resolver library to arrange for TCP/IP name service
4. Bring interfaces up and down, and set their IP addresses and netmasks
5. Set the default route in the kernel routing table
6. Describe the difference between TCP and UDP services
7. Understand the significance of the /etc/services file and well-known port numbers
8. Configure the inet daemon, which controls many Internet services
9. Briefly describe many common services, and use telnet to contact servers directly
10. Use the ping command to test network connectivity
11. Use the netstat command to examine kernel tables pertaining to networking
12. Use the traceroute command to discover network paths
13. Use tcpdump to examine all network traffic

The TCP/IP Protocol has played an essential role in the development of the internet. It may very well be argued that without the the seven layers of the OSI model, the internet may never have come into existence.

Internetworking with Linux has been the most popular choice of developers. Not only in the server world where Linux has made its mark but also in the small embedded network OS market, Linux is the most popular choice. All this requires an understanding of the TCP/IP code base. Some products require implementation of firewall, and others require implementation of IPSec. There are products that require modifi cations in the TCP connection code for load balancing in a clustered environment. Some products require improving scalability on SMP machines. Most talked about is the embedded world, where networking is most popular. Real time embedded products have very specific requirements and need huge modifications to the stack as far as buffer management is concerned or for performance reasons. All these require a complete understanding of stack implementation and the supporting framework.