SSH and CLI tips

Listing commands

When we wish to configure a router or switch, we obviously use commands but we may not know every command.

Connect to your router first in user mode.

 At the command prompt hold down shift + ? You should now see a list of commands available in use mode

Router>?

Exec commands:

 <1-99>               
Session number to resume

connect
Open a terminal connection

disable               
Turn off privileged commands

disconnect         
Disconnect an existing network connection

enable                
Turn on privileged commands

exit                      
Exit from the EXEC

logout                
Exit from the EXEC

ping
Send echo messages

resume               
Resume an active network connection

show                   
Show running system information

ssh                       
Open a secure shell client connection

telnet                  
Open a telnet connection

terminal             
Set terminal line parameters

traceroute         
Trace route to destination

 Now type enable command for priviaged mode and now shift +?

Now  you can see a lot more commands available to privilege mode

<1-99>     
Session number to resume

Auto                    
Exec level Automation

clear                    
Reset functions

clock                    
Manage the system clock

configure
Enter configuration mode

connect              
Open a terminal connection

copy                    
Copy from one file to another

debug                 
Debugging functions (see also ‘undebug’)

delete                 
Delete a file

dir                        
List files on a filesystem

disable               
Turn off privileged commands

disconnect         
Disconnect an existing network connection

enable                
Turn on privileged commands

erase                   
Erase a filesystem

exit                      
Exit from the EXEC

logout                
Exit from the EXEC

mkdir                  
Create new directory

more                   
Display the contents of a file

no                        
Disable debugging information

ping                     
Send echo messages

reload                 
Halt and perform a cold restart

reload                 
Halt and perform a cold restart

resume               
Resume an active network connection

rmdir                  
Remove existing directory

send                    
Send a message to other tty lines

setup                  
Run the SETUP command facility

show                   
Show running system information

ssh                       
Open a secure shell client connection

telnet                  
Open a telnet connection

terminal             
Set terminal line parameters

traceroute         
Trace route to destination

undebug            
Disable debugging functions (see also ‘debug’)

vlan                     
Configure VLAN parameters

write                   
Write running configuration to memory, network, or terminal

To list a command quicker if you know the first letter or part of the command name you simply need to type the following

Type in the command prompt c?

Now the terminal will show you all possible commands begging with “C”

Router#c?

clear clock  configure  connect  copy 

Now if we want to be a little more specific we just need to specify more letters. For example if we know the first 3 letters of a command we can do the following:

Type in the command prompt con? Now you will be listed commands that begin with con

Router#con?

configure connect

When you are in configuration mode and wish to run a command that only works with privileged mode you can issue the do command, for example if you are in configuration mod but wish to run the show running-config which only works in privileged mode, simply use the do command.

Type do show running-config or short do show run

Enabling SSH and disabling Telnet.

Logon to your router > enable (privileged mode)

Go to config mode config t

Give your router a name if not already configured ip domain name robertwelsh.local

Type User

Type username robert  password cisco

Type Crypto

Type Crypto key

Type Crypto key genet

Type crypto key generate rsa general-keys modulus 1024

Type crypto key generate rsa ? to see crypto commands

 Last enable SSH v2, use the following command ip ssh version 2

Now  we need to disable telnet line line vty 0 4

Type transport input ssh, now telnet is shutdown and ssh is enabled

Exit exit

Now we need to save the configuration, copy running config startup-config

Now test

Open your Putty client and first test login with telnet, should not work

Now try with SSH, you should be able to login, you will be presented with a certificate