(PacketTracer is an auxiliary learning tool released by Cisco Enterprises. It provides a network simulation environment for beginners to design, configure, and troubleshoot networks for Cisco network courses. This tutorial is developed for the version of packettracer 4.1, which is very helpful for beginners to CCNA and first-time use of packettracer. In addition to some advanced functions, version 4.1 can meet the needs of beginners. (I also copied it from someone else))