Dynamips is an emulator

Emulator

In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...

 program that was written to emulate Cisco

Cisco

Cisco may refer to:Companies:*Cisco Systems, a computer networking company* Certis CISCO, corporatised entity of the former Commercial and Industrial Security Corporation in Singapore...

 routers. Dynamips runs on Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 , Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 or Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 and can emulate the hardware of the Cisco series routing platforms by directly booting an actual Cisco IOS software image into the emulator.

Dynamips development has stalled since version 0.2.8-RC2, released in October 2007. There are a few add-ons written for it. One of the most popular is Dynagen, which is a front-end add-on that allows the use of an INI configuration file to provision Dynamips emulator networks. Other popular add-on is GNS3, which is graphical front end for Dynamips and Dynagen. The source code is licensed under the GNU GPL.