Suggestions and ideas to help build System Administrator skills:
- Install Linux on a home machine and play with it. We tend to use Debian, Ubuntu, and Mint (all Debian-based). Here is a list of downloadable books on Linux if you need some introductions, Here is some good reference materials. In particular study Linux/Unix Networking (see 1 and 2).
- Learn the difference between the command line tools that you would use to make a quick but ephemeral changes (like ifconfig and ip) and the config files that hold the permanent changes and the other commands that cause the config files to be reloaded. These are different in Debian and OpenWRT.
- Next get some old Linksys WRT54G or the like, and practice flashing and using OpenWrt. For extra credit you might familiarize yourself with pfSense which we use for our router / firewall firmware.
- Some concepts you should familiarize yourself with are: IP address (Internet Protocol address), netmask, subnet, broadcast address, MAC address, broadcast MAC address, VLAN (Virtual Local Area Network), and Trunk Ports.
- With VLAN, you should have an idea of how to use it on Linux, OpenWrt, and a typical Dell or Cisco Switch. Some tools you should be able to use are: Telent, FTP (File Transfer Protocol), SSH (Secure Shell), Vi (text editor), Vim (Vi IMproved), Bash Scripts, Cron (job scheduler), Nmap (Network Mapper), and for extra credit Wireshark (packet analyzer) … network simulator.