Cisco IOS Software
Connection to a router, boot-up an various options including basic IOS commands, modes (user mode / privilege mode) etc
Informational
Console cable is a "roll over" cable. The pin-outs are 'rolled over'
Pin 1 --> Pin 8
Pin 2 --> Pin 7
Pin 3 --> Pin 6
Pin 4 --> Pin 5
Pin 5 --> Pin 4
Pin 6 --> Pin 3
Pin 7 --> Pin 2
Pin 8 --> Pin 1
Terminal Emulation
Hyper-terminal - Limited (Comes with Windows)
Putty - only runs on Windows
Terra Term - Free
SecureCRT - Windows and MacOS
iTerm
Royal TSX
Modes
User Mode: Router>
view only mode
limited set of commands
basic monitoring commands
Privilege Mode (Enable Mode): Router#
allows a lot more show commands
allow debugging
used to configure the device
Global Config Mode: Router#(config)
change global parameters
MOTD (message of the day) - should be a legal entity. You can use any delimiter like hash (#) , a letter like 'c' etc and have to end with the same delimiter.
Line Mode - remember to use the 'login' parameter to use the password feature
console (console)
vty 0 4 (Used for telnet and ssh access)
login
password cisco
input transport telnet ssh
Useful Shortcuts
Other useful commands
Ctrl-U = deletes an entire line
Ctrl-C = cancels the command
Ctrl+Shift 6 x = breaks a command (like issue with domain lookup - arrgghhhhhhhhh)
Managing Cisco IOS Configuration
Running Config and Startup Config
copy run start (from RAM to NVRAM - overwrites the NVRAM config)
copy start run (merges the NVRAM with the RAM config)
show start run | b vty ---- b = begin
line vty 0 4
login
!
end
#config replace nvram:startup (replaces the config)
#erase startup-config
#copy run tftp://192.168.1.1/<config_name>
copy run tftp to copy start tftp = override or replacement
copy tftp to running config = merge
copy tftp replace = will replace the configuration file
Storing Files in Flash
show flash
copy running-config flash:/run1.cfg
more flash:run1.cfg will show the contents of the config file
Terminal Length & No IP Domain Lookup
When you do a show run, by default the config is restricted to a certain amount of lines (24) and it will then give out the --more-- command and then press spacebar and the next 24 lines will show etc etc
A tip is to use the command # terminal length 0, which shows the ENTIRE config in one go (good if you have long configurations etc)
Another tip is to use #no ip domain lookup when the router takes a long time to time out after trying to resolve a mistake you typed into a domain name!!
Basic Device Security
(config)#service password encryption
not very secure as it encrypts enable password with a type 7
(config)#enable secret CISCO
will see a 5 (md5) in front of encrypted password.
If you have both "enable password" and "enable secret" configured - the IOS will only use the "enable secret" password and ignore the other
LAB
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