Cisco Networking: Using PuTTY - dummies

By Edward Tetz

A terminal emulation program like PuTTY is necessary if you are connecting directly to your Cisco device via a cable or remotely connecting via Telnet or SSH. PuTTY is actively supported, in wide use and available for free from PuTTY download.

If you choose to download PuTTY, you have many programs to choose from on the download page, such as

  • PuTTY: The Telnet and SSH client itself

  • PSCP: A Secure Copy Protocol (SCP) client, such as command-line secure file copy

  • PSFTP: A Secure File Transfer Protocol (SFTP) client, such as general file transfer sessions like FTP

  • *PuTTYtel: A Telnet-only client

  • Plink: A command-line interface to the PuTTY back ends

  • Pageant: An SSH authentication agent for PuTTY, PSCP, and Plink

  • PuTTYgen: An RSA (Rivest, Shamir, and Adleman) and DSA (Digital Signature Algorithm) key generation utility

If you want to use PuTTY to make a terminal connection to your Cisco device, choose the full version of PuTTY, which is the first item on the list.

To make life easy, copy the PuTTY.exe file and paste it directly to your Windows folder (C:Windows). This allows you to launch PuTTY by choosing the Windows Start menu→Run, as shown in the following figure.

In addition to making PuTTY easy to launch, after you have configured and saved a session, you can launch PuTTY and load a session automatically by using the PuTTY.exe -load COM command.


Depending on the security settings on your version of Windows, you may be asked for confirmation to launch the application.

After PuTTY opens, the standard PuTTY Configuration dialog box appears. You can fill in your configuration settings and then click the Open button to make the connection, which opens a command window. If you regularly make connections to that device, save your settings by providing a session name and clicking the Save button.

The following figureshows the session being saved for a serial connection through COM1 running at 9600 bps. After you save this connection, you can launch it automatically, by using PuTTY.exe -load COM from the Run dialog box. In most cases, you want to save sessions for your most used connections.


The settings you just saved work for most Cisco devices, but the actual recommended settings include a small adjustment in the PuTTY Configuration dialog box, as shown in the following figure.

These settings are a little slower than the default settings in PuTTY, so if your command window does not show the console data correctly, use these settings. Choose Connection→Serial in the left navigation pane, and put in matching configurations for

  • Connection Speed: 9600 bps

  • Data Bits: 8

  • Stop Bits: 1

  • Parity: None

  • Flow Control: None