Packet Tracer Version 5.3.3 Packet Tracer version 5.3.3 is a maintenance release that fixes functional and technical issues in the previous versions. Packet Tracer is a simulator that provides a learning environment for networking novices to design, configure, and troubleshoot computer networks at a CCNA-level of complexity. Having a good environment is very importent for practicing CCNA, some of you might have a great lab full of cisco routers, switches and firewalls, which is the best, but Cisco introduced Packet Tracer a Router Simulator for those who have only one computer at their bedroom's and thinking how to practice without any router or switch?.