We can install the following programs completely free of charge on our computer, with the aim of creating complex networks and simulating their operation in real life. In this way, in the event that we detect a problem that can be transferred to real life, to the final installation that we are going to configure, we will be able to solve it as soon as possible and find a solution.
Cisco Packet Tracer
The first network simulator we want to talk about is Cisco Packet Tracer. It is one of the most used and complete that we can find. It has been developed by Cisco. In fact, it is the application that they recommend when we have to test some of their products, such as routers, network switches, hubs, servers, etc. It is not a complex tool, since it is easy to use. It is also free and allows you to perform all kinds of network virtualization.
This program is mainly aimed at users who want to obtain the different Cisco CCNA certifications, since it will allow us to study and learn how switching and routing works in Cisco iOS, the Cisco operating system that we have in our routers. When we want to learn with simulators or emulators for CCNP or higher certifications, this simulator will fall short, since it does not have all the more advanced configuration options that other simulators do incorporate.
Until the release of Cisco Packet Tracer 6.X, it was not necessary to register on the official Cisco website, we simply downloaded the simulator and could start performing the different test scenarios. Starting from Cisco Packet Tracer 7.0 release, Cisco needs you to register on the website completely free of charge, and log in to the program, otherwise you will have a lot of limited functionality. Our recommendation is that you always download the latest version available, but you will have to register with Cisco to later log in to the program.
If you want a software simulator that works very easily and quickly, with very little resource consumption because it’s all a simulation, then this program is the ideal one for you. In addition, there are a large number of tutorials on the Internet about its operation and also about how to make different assemblies through this software. Other programs like GNS3 or Eve-NG had clearly surpassed the functionalities and possibilities of CPT (Cisco Packet Tracer), but in the latest versions Cisco has done a great job improving its network simulator.
We recommend download cisco packet tracer from the official website.
Another network simulator that we can use is GNS3, which stands for Graphical Network Simulator. It has the peculiarity of being open source and has been designed to be able to simulate more complex networks in a simple way. Your goal is to simulate as closely as possible what it would be like in real life. Once again we are dealing with a free and open source program, very useful for engineers, administrators and anyone who is preparing certifications for Cisco or Juniper. It is used to carry out all kinds of tests and thus be able to test knowledge, solve possible errors that appear, etc.
GNS3 allows you to load the binary images of the Cisco operating system and run it in an emulated way, in addition, we could connect the GNS3 to the wired or WiFi network cards of the real equipment, to interact with this emulator and give it greater realism. Another very important feature is that it will allow us to add virtual machines to internal networks, in this way, we could design a complex network and then connect a Windows or Linux VM for further testing.
GNS3 uses the Dynamips, VirtualBox and Qemu modules. In this way, it allows us to offer an experience that is as real as possible to the different operating systems of the routers and network devices. It is an application multi platform, as it is compatible with Windows, Linux and macOS operating systems. The best thing you can do is install the GNS3 server in a virtual machine with VMware or Virtual Box, and later from the GNS3 «Client» connect to this virtual machine, in this way, we will have the maximum possible efficiency and the program will work really well .
GNS3 is a more difficult program to configure at first than Cisco Packet Tracer, but once you get to know it we’re sure you’ll love it, in fact, it’s our favorite network emulator due to all the advanced features it has. If, in addition to learning about networks with routing and switching, you want to learn about computer security, this emulator will allow you to connect virtual machines and run Python scripts without problems.
You can download the app from its Web page official. There you will also find tutorial videos and information to learn more about its operation and everything you can get, one of the strong points of GNS3 is that it also has a large number of videos on YouTube about very complex network setups, ideal for learning.
Eve-NG or also known as Emulated Virtual Environment Next Generation, is a program that allows us to simulate virtual networks from multiple providers. This program has been developed for home users or small businesses where they want to simulate their networks and configurations. Unlike the previous two programs, we have both a “Community Edition” edition that is completely free, and also a professional version with an annual payment. Both GNS3 and Eve-NG need the software images of the network devices, and in many cases it is not possible to get them for free. Eve-NG consumes very few resources and we would only need a program like PuTTY to access and modify the topology of the network.
This program will allow us to pass the certifications of Cisco, Juniper and also other manufacturers such as CheckPoint, PaloAlto, F5 and many more, since it allows a large number of network manufacturers. The design of the graphical user interface is very intuitive and we have many configuration options, in addition, being multi-manufacturer we can create complex networks made up of different manufacturers. Other features are that we will have hardware acceleration with KVM to have the best performance, we can have a complete HTML5 interface, it allows multi-user to simultaneously access the same project, we can pass a real network to the virtual one for testing and we can even create images customized with Visio to later embed it in Eve-NG.
We recommend access the official website of Eve-NG where you can find the links to download and all the information about this network simulator.
Virtual Internet Routing Lab or also known as VIRL, is the advanced emulator created by Cisco to learn about networks, and is aimed at both private users and educational centers. This software allows us to emulate very complex networks with the greatest possible realism. VIRL requires an annual subscription to have access to all supported images, it is very easy to use (more than GNS and Eve-NG). This program needs a terminal application like PuTTY to execute the different commands. In addition, VIRL works much more optimally on computers that have limited hardware, since it makes optimal use of the available resources.
If you are thinking of getting certifications such as Cisco’s CCNP or CCIE, using VIRL for training will be essential, and it is what Cisco recommends to successfully pass these certifications, however, GNS3 would also be a very good option for these certifications, but with VIRL you make sure you have the latest versions of the Cisco operating system for routers and switches.
We recommend access the official website of Cisco VIRL where you will find all the details to use this network emulator.
If you’re looking for something more specific to testing and research labs, netsim is an ideal program for it. It allows you to simulate networks with a significant amount of hardware and carry out tests to set up a network. It has similar features to the two previous options we have seen.
You can download the latest version from its website. It is a tool used by hundreds of organizations in many countries around the world, with features that are adapted both at a business level and also at a domestic level, to carry out tests that we need to simulate a network.
This application can be implemented in the operating system Windows. You will be able to carry out very diverse simulations, for different infrastructure environments, such as autonomous vehicles or manufacturing equipment.
In short, these are some of the options that we have available to be able to carry out network simulations. They are ideal tools for those who need to configure any type of network, whether at a business or home level, and want to carry out tests to be able to detect possible errors and solve them. We have shown some free applications that offer everything you need for it. Also, many of them are cross-platform, so you can use them on different operating systems where you need to perform the tests.