Blog: SSH

I've used the open source telnet/ssh client Putty for many years to manage remote machines. Recently I was using a blog post to setup a virtual machine to be used as a web server. The instructions were complete, but the commands were long and difficult to retype. I wanted to copy and paste but I couldn't use the Ctrl-V to paste in Putty because the key sequence is just sent to the connected computer. It turns out copy and paste is extremely easy in Putty, but you need to read the help file. Copy and Paste works with the mouse. Select any text with the left mouse button and it is immediately copied in the Windows clipboard. Right-Click to paste the contents of the clipboard into Putty. Here are a few bonus tips: [more]

Shift-Insert will also Paste into the Putty window.

Shift-Right-Click will bring up a context menu in the Putty window. The top menu item is Paste.

Double-Click will select the whole word below the mouse cursor and copy it to the clipboard.

Triple-Click will select the whole line below the mouse cursor and copy it to the clipboard.


If you use the setup wizard for Cisco ASA appliances to allow SSH access it doesn’t auto-generate a key.  It will create the access-rules, but you still won’t be able to SSH to the firewall until the key is generated.  The quickest way to generate the key is via the command:

generate crypto key rsa modulus-size” [more]

Note: The modulus-size can be 512, 768, 1024, or 2048.  The value of 1024 is recommended.


One of our customers had a problem with Platespin backing up a machine to their DR VMware server.  It turns out that ESX (starting in 3.5, but can include previous builds because of security patches) has a configuration file that can prevent virtual machines from booting if there is something in the virtual floppy or CD-ROM drive.  The fix is to edit the configuration files, using SSH to connect to the ESX console and edit the configuration files with vi. [more]


I was researching a way to do major router changes remotely.  I found that if I tftp’ed a new configuration directly to NVRAM and replaced the startup-config file, then reloaded the router, all changes would go into effect.  While testing this process locally, I found out that when the router was reloaded with the new configuration file, the SSH encryption keys got erased and had to be regenerated.  So if this process is used, make sure telnet is enabled on the VTY lines so that you can get back into the router!