IOS is the OS running on the Cisco switches. It can be terrifying, because one wrong move and you've kicked ~~redbrick~~ DCU off the internet. It's also very different to anything running on any of the servers.
A Quick Walkthrough
Be careful, don't BREAK it
When you log in first, you might have a prompt looking something like
This indicates you're in user mode. To change stuff, you'll want to go to
privileged mode. Type "enable" and hit enter. Enter the root password. Then hit
hadron>enable Password: hadron#
Wowsers, your shell prompt has changed. The # indicates root, like on a Unix system. You can also break things from this point on. So again, please don't break anything.
Let's look at some information about the switch. Type
hadron#sh ver Cisco IOS Software, C3560 Software (C3560-IPSERVICESK9-M), Version 12.2(50)SE3, RELEASE SOFTWARE (fc1) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2009 by Cisco Systems, Inc. Compiled Wed 22-Jul-09 06:41 by prod_rel_team Image text-base: 0x01000000, data-base: 0x02D00000 (...lots more information...) hadron#
Now examine the running config. Type
Current configuration : 6889 bytes ! version 12.2 no service pad service timestamps debug uptime service timestamps log uptime service password-encryption (...lots more information, until you get to...) interface GigabitEthernet0/1 description link to enzyme switchport access vlan 122 no cdp enable ! interface GigabitEthernet0/2 description currently unused switchport access vlan 122 no cdp enable ! interface GigabitEthernet0/3 description blinky switchport access vlan 122 no cdp enable ! interface GigabitEthernet0/4 description Carbon.external switchport access vlan 122 no cdp enable ! (...You can guess what these are... Lots more of these... and a bit of stuff at the end...) hadron#
Now let's change something. Something I had to do today was to change the
description on port 45, because I'd plugged something new in. Go into config
hadron#conf t hadron(config)#
Your prompt has changed! You're now in config mode. Now you can really fuck
things up. You want to configure an interface, so type
interface followed by
the name of the interface you want to feck with. The full name is shown when
you do that
sh running thing you did earlier - in our case,
hadron(config)#interface GigabitEthernet0/45 hadron(config-if)#
Prompt change again! Now that you're set to play with this interface only, you're a little safer again - if you break it, it'll probably only break that one interface. Probably. Maybe. Unless it's the uplink port, in which case, please please please be careful. So, we wanted to change the description. Fairly simple. Just type "description" followed by the new description.
hadron(config-if)#description b4 mgmt
Done! There's lots of other things you can poke at from here, like turning a
port on/off, playing with VLANs, etc. If in doubt, ask for help, and/or read a
book, and/or take a course in advanced networking, and/or sacrifice a goat for
good luck. You still need to get out of config mode and save your config. Type
end (your prompt will change) followed by
write to save your changes.
disable if you want to drop to user mode (no, it won't disable
the switch...I think). Type
logout to get back to the sane world and close
your IOS SSH session completely.
hadron#logout Connection to hadron.mgmt closed. werdz@sprout:~$