Using Putty with Dynamips and GNS3

If you are like me, you may be cutting corners by using Dynamips and GNS3 with at least some of your preparation for the CCIE Lab.  For those of you who are not familiar with Dynamips and GNS3  and are interested in an actual Cisco Hardware virtualization platform, you should check it out here.  Please note that not all platforms are emulated and they do not make the actual OS images available from the site for licensing reasons.

GNS3 is the graphical interface that gives easy access and configuration to the Dynamips Hypervisor.  From GNS3, you can build an infrastructure in a graphical manner.  You can also launch a console connection into the router.  These sessions will just use the default telnet application for the operating system.  Personally, I prefer Putty.  It is much better about certain things like scroll back and the ability to turn logging to file off and on at will.

To change the configuration of GNS3 to use Putty is simple and straightforward.  Simply copy the putty.exe to a known location, or to somewhere this is in the system search path (i.e. %path%).  Then launch GNS3.  In GNS3 choose “Edit” then “Preferences”.  I am using 0.5 beta.  With this version, you will find a box for “Terminal Command” in the General subsection.  Typical in a Windows system, you will find it set to “start telnet %h %p”.  To use Putty instead, use one of the following methods:

“<PathToPutty>\putty.exe” telnet://%h:%p

“<PathToPutty>\putty.exe” -telnet %h %p

Omission of the start command should be fine.  If you do use the start command, the first set of double quotes is assumed to be the title.  So you may need to eliminate the quotes preceding and following the putty command and location (assuming you have no spaces in your path), or you can put something else in another set of double quotes immediately after the start command to pass the title value to the start command.  In any case, this should get you going in the right direction if you prefer Putty (or any other console client for that matter).

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About Paul Stewart, CCIE 26009 (Security)

Paul is a Network and Security Engineer, Trainer and Blogger who enjoys understanding how things really work. With over 15 years of experience in the technology industry, Paul has helped many organizations build, maintain and secure their networks and systems.
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