Cisco Iou L3 - Gns3 May 2026

In GNS3, go to Edit > Preferences > QEMU & IOU > IOU Devices . Click New .

IOU requires a license file called iourc . You must place a valid iourc file in the GNS3 config directory (usually ~/.GNS3/ on Linux/Mac or %LOCALAPPDATA%/GNS3 on Windows). A sample iourc entry looks like: [license] hostname = 12345678 Cisco IOU L3 - GNS3

Use it as a learning tool, respect software licensing, and upgrade to CML images when you need 100% feature parity with modern hardware. Do you still use IOU in your labs? Or have you switched entirely to EVE-NG? Let me know in the comments below! In GNS3, go to Edit > Preferences >

Choose the ID (e.g., [L3] Cisco 7200 (IOU) ). Set the RAM to 512 MB (even 256 works, but 512 is safe). You must place a valid iourc file in

Here is everything you need to know about why IOU L3 still matters and how to make it sing in GNS3. Simply put, IOU (often called IOSv or L2/L3 IOU ) is an emulator that runs Cisco IOS directly as a Linux userspace process. Unlike traditional Dynamips (which emulates the CPU), IOU virtualizes the IOS environment.

GNS3 will ask for the path to your IOU binary (e.g., L3-ADVENTERPRISEK9-M-15.4-2T.bin ).