Unzip Cisco IOS images for Dynamips

I have a directory ‘dynalab’ in my ‘Documents’ where I have put ALL my Dynamips / Dynagen related files. I created a directory there which has all my IOS images, this makes more sense to my mind. Makes it easier to backup.

gf:Documents gregferro$ mkdir dynalab
gf:Documents gregferro$ cd dynalab
gf:dynalab gregferro$ ls
gf:dynalab gregferro$

You can copy IOS images as normal using the Finder into the dynalab directory. To uncompress the images you can either download the Zipeg program (use a search engine to find it), or use the command line as follows:

gf:dyncode gregferro$ unzip -p c1700-sy-121-9.bin > c1700-sy-121-9.image
warning [c1700-sy-121-9.bin]: 16304 extra bytes at beginning or within zipfile
(attempting to process anyway)
gf:dyncode gregferro$

I have renamed the IOS file from .bin to .image so I can determine that it has been uncompressed. I keep the rest of the name the same, because that tells me the feature set of the image.

Now your images are ready to use. You can see the script I use to start Dynamips / Dynagen in a earlier post.

About Greg Ferro

Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count.

He is a host on the Packet Pushers Podcast, blogger at EtherealMind.com and on Twitter @etherealmind and Google Plus

You can contact Greg via the site contact page.

  • http://eee Joel

    wow.. thanks dude, am surprised that no one commented yet. nice work. coz i wasnt able to decompress it without ur instructions…

    • http://etherealmind.com Greg Ferro

      Thanks, appreciate the feedback.

  • Richard

    OK – I must be stupid. I downloaded the ZiPeg you recommended but it will not open any of my .bin IOS image files…and I cannot seem to find anywhere where it says it will do so…

    Any help on this..?

    Thanks :-)

  • http://etherealmind.com Greg Ferro

    Try renaming the file with a .mz extension. I haven’t done this for while so I can’t quite remember.

  • Al

    Thanks! This article solved the issue I had attempting to boot 2600-series routers in GNS3.

  • quantump

    great help, been using gns3 for a while and experienced slow down at the start whenever the routers bootup. but now it goes straight to config dialog. great post! great help! thanks!

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