Wednesday, 29 December 2010


Well I have been playing about with GNS3 a little ove the holidays and looking at how it works. I must say that it is user freindly for some things such as routers but other thing, oh boy can it be troublesome.

GNS3 does not natively support switches, ok I think we all knew that. It does however let you add a switch module to your routers and I will be playing with this a little.

Its when you look at GNS3 and what it can do that you really really start to delve deep into it.

I had the pleasure or misfortune of deciding that if I want to look at security later in the year how good would it be to get te ASA working in it.

Well that in and of itself was a challenge but I managed to get it working. OK I still have a minor issue in that I am unable to save my configs but from a lab perspective thats no big deal as all it really means is having to type everything in again and again. Well hey thats what i would do anyway so I can cope with that. I could also save the configs to a text file.

I also dont have it working in multiple context at the moment but hey little steps. Considering I have no experience currently just getting used to setting one up will be a big step.

Then however I decided to get ASDM working, that was not too hard but you rereally need it working as thats the straight forward way to setup an ASA. Well I managed to get it working at last, the trick there is to use Fiddler but as it intercepts we traffic and sends it to the ASA it screws up your ability to browse the internet.

OK at the end of the day I can practice on it and get some use but I will still probably but and ASA.

Before anyone asks I will not be doing a write up of how to install it ananytime soon. Firstly I want to get all the gremlins sorted, seconly I have other things to focus on, thirdly I really like cables and devices so will practice on a real ASA when the time comes, ASA in GNS3 is a nice to have but GNS3 is really for routers in my humble opinion.

Just a cautionary note, there is an aweful lot of stuff on the internet about getting ASA to work in GNS3, much of it is absolute bollocks I am afraid to say, its pretty straight forward if you have the right stuff as I found out but I still have gremlins. Have fun sorting out the wheat from the chaff.

Here is a link to help you get started ASA on GNS3

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