Your first Cisco lab: the CLI basics

1. 1

   Import and start the lab

   Download first-cisco-lab.yaml below and import it into CML (Dashboard → Import), then press Start. When the nodes are running, click R1 and open its console. New to CML? The getting-started guide covers installing it.

   You should land at a Router> prompt. If you're asked “Would you like to enter the initial configuration dialog?”, type no and press Enter.

   

2. 2

   Meet the command line (user EXEC mode)

   That Router> prompt is user EXEC mode — read-only. Four habits to build now:

   • Help: type ? to list what you can do, or show ? for everything show can do.
   • Tab completion: type pin then press Tab — IOS finishes it to ping.
   • Abbreviation: shorten any command to the fewest unique letters — sh ip int br is show ip interface brief.
   • Command history: press ↑ to bring back your last command.

   Nothing you do in user EXEC can change the device — explore freely.

   

3. 3

   Enter privileged EXEC mode

   Type enable. The prompt changes from > to # — privileged EXEC mode, with full access to view and change. This lab has no enable password set, so it just works.

   Have a look around before you change anything:

   Router# show ip interface brief
   Router# show version
   Router# show running-config

   What you should see from show ip interface brief — the Ethernet interfaces are all down, because we haven't configured them yet:

   Interface              IP-Address      OK? Method Status                Protocol
   Ethernet0/0            unassigned      YES unset  administratively down down
   Ethernet0/1            unassigned      YES unset  administratively down down
   Ethernet0/2            unassigned      YES unset  administratively down down
   Ethernet0/3            unassigned      YES unset  administratively down down
   Loopback0              unassigned      YES unset  up                    up

   Loopback0 is a virtual interface — ignore it for now. show version gives the IOS version and uptime; show running-config is the live configuration. We only need Ethernet0/0 for this lab.

4. 4

   Enter global configuration mode

   Enter global configuration mode with configure terminal (or conf t). The prompt gains (config):

   Router# configure terminal
   Enter configuration commands, one per line.  End with CNTL/Z.
   Router(config)#

   Everything you type here changes the running configuration immediately.

5. 5

   Set the hostname

   Give the router a name. The prompt changes the instant you press Enter:

   Router(config)# hostname R1
   R1(config)#

6. 6

   Configure the interface and bring it up

   Give Ethernet0/0 an address and turn it on. interface Ethernet0/0 drops you into interface configuration mode ((config-if)#):

   R1(config)# interface Ethernet0/0
   R1(config-if)# description Link to PC1
   R1(config-if)# ip address 192.168.1.1 255.255.255.0
   R1(config-if)# no shutdown

   What you should see — a moment after no shutdown:

   %LINK-3-UPDOWN: Interface Ethernet0/0, changed state to up
   %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to up

   description is optional — it just labels the port. Interfaces are administratively down by default; no shutdown enables them. The mask 255.255.255.0 is a /24.

7. 7

   Back out and verify

   Return to privileged EXEC with end (or Ctrl+Z), then check your work:

   R1(config-if)# end
   R1# show ip interface brief

   What you should see — Ethernet0/0 is now up/up with your address:

   Interface              IP-Address      OK? Method Status                Protocol
   Ethernet0/0            192.168.1.1     YES manual up                    up
   Ethernet0/1            unassigned      YES unset  administratively down down
   Ethernet0/2            unassigned      YES unset  administratively down down
   Ethernet0/3            unassigned      YES unset  administratively down down
   Loopback0              unassigned      YES unset  up                    up

   Both right-hand columns need to read up — line status, then protocol.

8. 8

   Ping PC1 — the payoff

   PC1 is already set to 192.168.1.10 with its gateway at 192.168.1.1 — the address you just gave R1:

   R1# ping 192.168.1.10

   What you should see:

   Type escape sequence to abort.
   Sending 5, 100-byte ICMP Echos to 192.168.1.10, timeout is 2 seconds:
   .!!!!
   Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/2 ms

   Each ! is a reply; a . is a timeout. The first packet often shows a . while ARP resolves PC1's MAC address — run the ping again for a clean !!!!!.

9. 9

   Save your work

   Your work lives in the running-config (RAM). A reload boots from the startup-config (NVRAM) instead and loses it. Save the running config to startup:

   R1# copy running-config startup-config
   Destination filename [startup-config]?

   Press Enter to accept the destination.

   Building configuration...
   [OK]

   write memory (or wr) does the same thing.

10. 10

    Find your way around the modes

    The whole map you just used:

    Router>User EXEC — read-only. enter with: log in

    Router#Privileged EXEC — full view + save/reload. enter with: enable

    (config)#Global config — change the device. enter with: configure terminal

    (config-if)#Interface config — change one interface. enter with: interface Ethernet0/0

    To move back out:

    • exit — steps back one level (interface → global → privileged).
    • end or Ctrl+Z — jumps straight back to privileged EXEC from any config mode.
    • disable — drops from privileged EXEC back to user EXEC.

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