Solution: Cisco IOS images are copyrighted, you need a CCO log on to the Cisco website (free) and a contract to download them.There are others ways for getting. Here is the direct download link of Cisco IOS Images For GNS3.These have been tested with latest GNS3. Feel free to drop comments.

1. Cisco Ios Images For Gns3 Download Free

Working 3745 IOS download for Gns3

What is IOS image?

IOS image is software or Operating System used in most Cisco routers and switches. IOS image support different packages like routing, switching and inter-networking etc. You can use these IOS images with GNS3. Gns3 is one of the famous network simulator and its hot feature is that it can run the real Cisco IOS image, as compare to other network simulator like packet-tracer which perform all functions base on programming. If you are beginner then learn more here:Cisco Switch Basic Configuration, how to use or configure GNS3

Remember only the c7200 series ios images get newer IOS images. According to Cisco all other platforms are now “end of life”, but you can used these older ios images as well with Gns3.

Gns3 3745 IOS image Details

Cisco 3700 Series are the multi-service routers provide LAN/WAN connectivity, new high-density service modules, and support for multiple advanced integration modules. You can use NM-16ESW module with this 3745 IOS, which will enable the switching functionality in GNS3. In this way you will be able to perform different switching labs with GNS3 like Vlans, inter-vlan (Router on stick), VTP (vlan trunking protocol), different multi-layer functionality etc. learn more about Layer 3 Switching vs Routing

From here you can download Cisco 3745 IOS image for your GNS3 and perform different GNS3 labs with this IOS. Remember this IOS is only for informational, practice purposes and for GNS3 used. If you need the IOS for your real hardware then it is better to Contact Cisco for latest and best IOS for your device. Following is the details and recommended setting of Gns3 3745 IOS image for your GNS3 setup. This Image was tested with Gns3 1.1 and i hope this will also work fine with the latest GNS3 version as well.

IOS version =12.4.25d (Mainline)

File name: c3745-adventerprisek9-mz.124-25d.bin

Minimum RAM: 128 but alteast 256MB recommended

Best idle-PC value: 0x60aa1da0 , you can set other idle PC value as well

Here is the link from where you can download IOS for your Gns3

Other IOS image on this Website:

Download Cisco IOS Images For GNS3

Below are all the working versions of Cisco IOS which we have tested with the latest version of GNS3. You can Download Cisco IOS Images For GNS3 from below links directly. Feel free to download them and use them for your Cisco certifications studies.If you face any problem setting it up with GNS3 drop us a message and we will get back to you asap.

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Download All above files in one go Click Here (File size 182 MB)

GNS3 is an open source (GNU GPL) software that simulates complex networks while being as close as possible from the way real networks perform, all of this without having dedicated network hardware such as routers and switches.

GNS3 provides an intuitive graphical user interface to design and configure virtual networks, it runs on traditional PC hardware and may be used on multiple operating systems, including Windows, Linux, and Mac OS X.

In order to provide complete and accurate simulations, GNS3 actually uses the following emulators to run the very same operating systems as in real networks:

• Dynamips, the well known Cisco IOS emulator.
• VirtualBox, runs desktop and server operating systems as well as Juniper JunOS.
• QEMU, a generic open source machine emulator, it runs Cisco ASA, PIX and IPS.

GNS3 is an excellent alternative or complementary tool to real labs for network engineers, administrators and people studying for certifications such as Cisco CCNA, CCNP andCCIE as well as Juniper JNCIA, JNCIS and JNCIE.

Minimum memory

The minimum RAM is the amount of memory needed for IOS to work at maximum capacity with most feature configured and activated. From experience you can usually use a bit less RAM just fine.You can also use gns3 on low end computer by using idle pc value

Recommended images

We really recommend using c3640, c3660, c3725, c3745 and c7200 IOS images listen above, they have proven to be the most stable in GNS3 provided you use the right amount of RAM and Idle-PC value.

Idle-PC value

Cisco Ios Images For Gns3 Download Free

This settings will help Dynamips to consume less CPU. It’s specific to each different IOS image.Idle pc value will be the best option to make Gns3 work smoothly on any computer. To learn how to setup Idle pc value check this post How To setup idle pc value easily