Learning the Cisco CLI! The operating system for cisco routers is called IOS Sounds like apple... It's a proprietary OS Let's look through Wikipedia a minute Been around a while We'll look at the interface thing again in a minute Proprietary OS - not based on Linux, FreeBSD, or anything else How do we get a terminal on a real switch or router? Good question... Couple options: Serial link USB SSH I really need to see if IT will give me one Memory types: RAM: Working storage, like a PC Flash memeory: Used to store IOS itself ROM: Read-only, contains code to load IOS from flash NVRAM: Non-Volatile RAM, holds the startup configuration The question mark: Suppose we want to do something and have no idea what to type ? alone = list of commands ? after a command = help on that command Let's explore this a bit with show Priviledged commands: enable and disable will move modes here > vs. # on prompt Can start global configuration mode from here configure terminal Think of it giving you a configuration terminal Doesn't really configure the terminal, since it seems to spawn a new shell From global configuration mode, you can configure an interface interface "show" doesn't work in global configuration mode Think of it more like entering lines of a config file, one by one Autocomplete: In a lot of cases, you can type a subset of a full command Such as "config t" for "configure terminal" Can use tab to expand as well no: "no" undoes most things "no ip routing" or whatever Saving the current config as the startup config: copy running-config startup-config Can't just write "backup-config" or whatever Alright, can we apply this? Let's make a network with a couple computers on different IP ranges Then hook them to a router We can let them talk or not talk, depending on if we route traffic between them Because a bunch of you are going to ask: Yes, you can set up an old PC with Linux and do this exact thing No, it won't have the IOS interface No, data centers don't usually do that Big Bear Tires... Lab today: Practice this stuff! Set up something with a router and 4 computers Either pick a big router, or use a couple switches too Use at least two IP ranges that don't overlap Can use subnet mask to divide, or just pick different blocks completely Set it up so all the computers can communicate I'm not going to give you detailed instructions this time Use your own creativity! Probably run into way more interesting problems this way