So, ifconfig, netstat, route are no longer maintined. Here's info on the newer alternatives:
Doug Vitale Tech Blog: Deprecated Linux networking commands and their replacements

Linux: Where the Jobs (and Bigger Salaries) Are

Here are three links I used when reviewing for the RHCSA exam:
RHCSA: My study guide
Musings on Information Technology - A view from the trenches
Unofficial RHCE Study Guide

These I used for the RHCE:
RHCE: My study guide
Musings on Information Technology - A view from the trenches

Want a Job? Learn Linux