The 5.1 version of Cisco PacketTracer is provided as a free download on our website. The following version: 4.1 is the most frequently downloaded one by the program users. PacketTracer5.exe is the common file name to indicate the Cisco PacketTracer installer. This download was checked by our built-in antivirus and was rated as clean. The program lies within Internet & Network Tools, more precisely Network Tools. This free program was originally created by Cisco Systems, Inc.
From the developer:
Cisco Packet Tracer is a powerful network simulation program that allows students to experiment with network behavior and ask “what if” questions. As an integral part of the Networking Academy comprehensive learning experience, Packet Tracer provides simulation, visualization, authoring, assessment, and collaboration capabilities and facilitates the teaching and learning of complex technology concepts.
You may want to check out more software, such as Cisco Packet Tracer, Cisco IPS Manager Express or Cisco Phone Designer, which might be similar to Cisco PacketTracer.