Cisco : Enable SSH on Cisco Switch, Router and ASA

When you configure a Cisco device, you need to use a console cable and connect directly to the system to access it. Follow the SSH setup below, will enable SSH access to your Cisco devices, since SSH is not enabled by default. Once you enable SSH, you can then access it remotely using SecureCRT or any other SSH client.

Set hostname and domain-name

The hostname has to have a hostname and domain-name.

switch# config t
switch(config)# hostname tpw-switch
tpw-switch(config)# ip domain-name

Setup Management IP

In the following example, the management ip address will be set to in the 101 VLAN. The default gateway points to the firewall, which is

tpw-switch# ip default-gateway
tpw-switch# interface vlan 101
tpw-switch(config-if)# ip address

Generate the RSA Keys

The switch or router should have RSA keys that it will use during the SSH process. So, generate these using crypto command as shown below.

tpw-switch(config)# crypto key generate rsa
  The name for the keys will be:
  Choose the size of the key modulus in the range of 360 to 2048 for your
    General Purpose Keys. Choosing a key modulus greater than 512 may take
    a few minutes.

How many bits in the modulus [512]: 1024
  % Generating 1024 bit RSA keys, keys will be non-exportable...[OK]

Setup the Line VTY configurations

Setup the following line vty configuration, where input transport is set to SSH only. Set the login to local, and password to 7, and make sure Telnet is not enabled:

tpw-switch# line vty 0 4
 tpw-switch(config-line)# transport input ssh
 tpw-switch(config-line)# login local
 tpw-switch(config-line)# password 7
 tpw-switch(config-line)# exit

If you have not set the console line yet, use the following:

tpw-switch# line console 0
tpw-switch(config-line)# logging synchronous
tpw-switch(config-line)# login local

Create the username password

If you don’t have an username created already, here is how:

tpw-switch# config t
Enter configuration commands, one per line.  End with CNTL/Z.
tpw-switch(config)# username thepacketwizard password tpwpassword123
tpw-switch# enable secret tpwenablepassword

Make sure the password-encryption service is turned-on, which will encrypt the password, and when you do “show run”, you’ll see only the encrypted password and not clear-text password.

tpw-switch# service password-encryption

Verify SSH access

From the switch, if you do ‘show ip ssh’, it will confirm that the SSH is enabled on this Cisco device.

tpw-switch# show ip ssh
 SSH Enabled - version 1.99
 Authentication timeout: 120 secs; Authentication retries: 3

After the above configurations, login from a remote machine to verify that you can ssh to this cisco switch.

In the example, is the management ip-address of the switch.

TPW-Remote-Computer# ssh
 login as: thepacketwizard
 Using keyboard-interactive authentication.


You are now setup and logged in on SSH!

To read more on SSH visit:

Data Centre : Post DC Move Unracking

We moved our company internal Data Centre to a COLO Facility 2 weeks ago, here is what is left. Before and After Pictures, as well as a photo of the “Boneyard”. A pretty good haul for E-Wasting:

2x Cisco 6909’s

3x Cisco 6513’s

8x Cisco ASA’s

2x Brocade Loadbalancers

4x Cisco 2900 Routers

2x Cisco Nexus 5k

1x Cisco Wireless LAN Controller


Cisco : Serial Numbers

Today I have spent some time trying to find serial numbers on multiple Cisco devices, some Routers, Switches, Firewalls and Wireless LAN Controllers. Here is 7 ways I have found:

  1. Locate the serial number tag on the device chassis.
  2. The serial number is displayed in the banner during boot.
  3. “show version” command. (Look for Processor board ID or S/N)
  4. “show inventory” command. (Look for Hw Serial# or SN:)(Also works on WLC’s)
  5. “show diag” command. (Look for Chassis Serial Number)
  6. “show hardware” command. (Look for Processor board ID or S/N)
  7. “show tech-support” command.