Firewall Testing

Normally you would need at least two computers to test a firewall. That is still an option, however recent builds of FireHOL ship with a tool, vnetbuild, which helps you to build whole virtual networks using only the standard network namespaces feature present in recent Linux kernels.

You can run any commands you want in the namespaces and they will behave with that view of the network. This is ideal if you want to control everything without the expense of setting up lots of real or virtual hardware.

Otherwise, if you only have one machine or you want to test your live firewall from outside, there are a number of online services.

Testing Tools

To test your firewall there are a few software tools and a few online services to help you. I suggest the following tools:

It is also possible to try out connections, see what effect your firewall is having and monitor exactly what is happening on the network with tools such as:

Other useful links:

Online Tools

There are a number of sites that offer firewall testing services to everyone:

Other testers on the net: