Free online courses usually don't offer college credit. These courses charge a nominal fee, but it's generally much less than what students would pay for the course if they were taking it at a traditional college.

Free Online Non-Credited Networking Courses

National Programme on Technology Enhanced Learning (NPTEL)

Computer Networks
Cryptography and Network Security

Massachusetts Institute of Technology

Computer System Engineering
Data Communication Networks
Information Technology Essentials
Network and Computer Security
Network Optimization

Rensselaer Polytechnic Institute

Broadband and Optical Networks
Computer Communication Networks
Experimental Networking

University of Michigan

Introduction to Information Studies
Networked Computing: Storage, Communication, and Processing
Networks: Theory and Application

Universiti Teknologi Malaysia

Telecommunications and Networking