Ubuntu – Managing Cisco Devices via Serial / Rollover Cable

KB ID 0000400 


A while back I ran though “Managing Cisco ASA devices via the ASDM with Ubuntu“, I prefer to work at command line, with a new firewall my only choice is via the console port, In a windows environment I can fire up Hyperterminal and I’m away. With Linux there a couple of things to do first.

ubunti serial to usb converter


Step 1 (Get the Serial / RS232 / COM Port working)

As pictured above, this is being done on my Acer Netbook so I don’t have a serial port. I need to use a USB to Serial converter, If your machine has a serial port then simply skip this section.

1. Plug in your serial converter and wait a few seconds, open a terminal window (Applications > Accessories > Terminal) and issue the following command,



2. Amazingly it looks like been installed with the correct driver, without any effort by me at all! Lets make sure, unplug the USB to serial converter then issue the following command,


Then plug the device back in and run the same command, notice the serial port has popped onto the list.


Note: If you not as lucky as me follow the excellent advice here to install the drivers you need.

Step 2 Install and Configure Minicom

1. Open a terminal window and issue the following command,

sudo apt-get install minicom

Tap in your password, then enter “Y” for yes when prompted.

install minicom

4. We need to know the connection name for the USB to Serial converter, issue the following command (See mines called ttyUSB0).

dmesg | grep tty

usb to serial driver ubuntu

5. Now lets fire up Minicom with the following command,

sudo minicom

Tap in your password again, then as requested press CTRL+A, then Z.

launch minicom

6. To configure the serial settings press O (that’s O for Oscar not zero).

linux setup serial port

7. Select “Serial Port Setup”.

8. Press A to set the device.

serial device

9. As we discovered (above) ours is called ttyUSB0, so change the device to /dev/ttyUSB0.

ubunti serial hypertemrinal

10. Press C to change the connection speed to 9600 baud, Press Q (to set 8 bits, no stop bit, and 1 parity bit. On mine this was set by default), press {enter} to exit.

ubuntu serial socket settings

11. Press F to turn off hardware flow control (Some posts will say leave it on, I generally turn if off and I’ve never seen anything break!). Press G to disable software flow control (if enabled).

ubunti to cisco asa

12. Then Select “Save setup as..”, and give is a sensible name. (If you went back too far simply press O again to get back here).

minicon cisco

13. Now the settings are saved you can launch them at anytime with,

sudo minicom {filename}

Note: Sometimes your serial drive gets locked up but a reboot will solve the problem.

minicom to asa

14. Here’s me connected to an ancient old catalyst switch.

manage asa form linux

15. And the baby PIX on my test network.

linux to cisco firewall

Note: If your keystrokes are not getting sent: From the main menu (CTRL+A then Z) Press E to turn on local echo.


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Author: Migrated

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