PEMU - Free Cisco PIX Firewall Emulator / Simulator


This is a guide on how to install a Free pix emulator / simulator onto a linux platform. You can also obtain the windows version, which you can find (along with other tutorials and forum) at

This software was written by mmm123, and is called PEMU, which is based on the QEMU emulator.

What do I need ?

You will need to the following in order to install PEMU, 

  1. Install Guide (How-to) - Linux Platform - click here
  2. PEMU Software - Linux Platform - download
  3. IOS Image - Obtained via the Cisco website

Please bear in mind you will need to unzip the PEMU software, in order to obtain your pemu_2008-03-03_bin.tar.bz2 which you can then use when going through the install guide above. You will also find in here a README file which also has some good information to help with the install.

What do I need to do ?

The best option with this version of PEMU is to use pcap, this means that you do not have to configure the ifup.ini file and the traffic should run much quicker then if just using tap.

You then configure your host (linux) interfaces to with a subnet of the same (or set them to promisc mode). And then run the PEMU command with the relevant switches (please see below).

Below is the command with the require switches. This presumes you are in the pemu directory, 

./pemu -net nic,vlan=1,macaddr=00:aa:00:00:02:01 -net pcap,vlan=1,ifname=eth0 -net nic,vlan=2,macaddr=00:aa:00:00:02:02 -net pcap,vlan=2,ifname=eth1 -serial stdio -m 128 FLASH

With all the information and tutorials above you should be able to configure this software without to many problems. If you do encounter any issues, visit the forum at and they should be able to help.

Finally a big thanks goes out to mmm123.