If you need to backup the configuration of a network device, such as a Cisco router, without going through the hassle of actually connecting up the network interfaces, you can relatively easily do so with a serial cable and PuTTY

  1. Issue the “terminal length” command so that the output from commands isn’t paged. Without this we’d have to prune out the “-more-” from the terminal output. 
    router# terminal length 0
  2. Configure Putty to log session output:
    1. Right-click the window title and choose “Change Settings…";
    2. In the tree menu on the left, select “Logging” beneath “Session”;
    3. Select the “All session output”; radio button and choose a suitable destination file;
    4. Finally, click “Apply” to dismiss the “PuTTY Reconfiguration” window;
  3. Issue the show running-config command;
  4. The configuration will now be stored in your text file.