Basic Cisco Network Configuration

Basic commands

Enter privileged mode

Router>enable or en
Router#

Enter global configuration mode

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

Exit the current configuration mode and return to the previous mode

Router(config)#exit
Router#

See the list of available commands in the current mode

Router(config)#?

This will display all available commands. If there is a -More-, you can either do it to display the next line or make a space to display the next page. To quit the display, press the Q key or CTRL + C combination

Save

Routeur#copy running-config startup-config or copy run start
Destination filename ?
Building configuration...

Routeur#wr
Building configuration...

Routeur#reload
Proceed with reload? [confirm]

Secure a router/switch

Set the name of the router and the domain name

Router(config)#hostname <name>
Router(config)#ip domain-name <domain_name>

Router(config)#no hostname
Router(config)#no ip domain-name
Router(config)#

Prevent unwanted DNS lookups

Router(config)#no ip domain-lookup

Set a console password

Router(config)#line console 0
Router(config-line)#password <password>
Router(config-line)#login
Router(config-line)#exit

Set a telnet password

Router(config)#line vty 0 4
Router(config-line)#password <remote_access_password>
Router(config-line)#login
Router(config-line)#exit

Set a preferred mode password

Router(config)#enable secret <password>

Router(config)#banner motd #

Router(config)#no banner motd

Encrypt passwords

Router(config)#service password-encryption

Add vlan to a switch

Switch(config)#vlan <number>
Switch(config-if)#name <name>

Switch(config)#no vlan <number>

Switch(config)#interface <interface> or interface range <interface>
Switch(config-if)#switchport mode access
Switch(config-if)#switchport access vlan <number>
Switch(config-if)#exit

Switch(config)#interface range fastEthernet 0/2-24

Switch static mapping

Switch(config)#mac-address-table static <mac_address> vlan <vlan> interface <output_interface>

Add a default gateway

Switch(config)#ip default-gateway <ip_address>

View and test

Router#ping <ip_address>

Switch#show interfaces

Router#show ip route or sh ip rou

Switch#show ip interface brief or sh ip int br

Switch#show ipv6 interface brief or sh ipv6 int br

IP addressing on router

IPv4

Add an ip address

Interface: Fa0/0
IP adress: 192.168.100.1
Subnet Mask: 255.255.255.0

Router(config)#interface fastEthernet 0/0
Router(config-if)#ip address 192.168.100.1 255.255.255.0
Router(config-if)#description <text>
Router(config-if)#no shutdown or no sh

Router(config)#int fa0/0
Router(config-if)#no shutdown or no sh

Remove an ip address

Router(config)#interface fastEthernet 0/0
Router(config-if)#no ip address

Router(config)#int fa0/0
Router(config-if)#shutdown or sh

IPv6

ipv6 routing is disabled on your routers which prevents ipv6 communication between different pc. You must activate it with this command:

Router(config)#ipv6 unicast-routing

IPv6 addressing with link-local

Router(config)#int fa0/0
Router(config-if)#ipv6 address FE80::1 link-local
Router(config-if)#no shutdown or no sh

Add IPv6 addressing

Router(config)#int fa0/0
Router(config-if)#ipv6 address 2001:....:1/64
Router(config-if)#no shutdown or no sh

Route

IPv4 Route static

Add a route

A static route connected directly and fully defined:

Router(config)#ip route <network_address> <subnet_mask> <output_interface>

A recursive static route:

Router(config)#ip route <network_address> <subnet_mask> <ip_address_of_the_next_device>

Router(config)#ip route <network_address> <subnet_mask> <output_interface> <ip_address of_the_next_device>

Remove a route

Router(config)#no ip route <network_address> <subnet_mask> <output_interface>

Router(config)#no ip route <network_address> <subnet_mask> <ip_address_of_the_next_device>

Default IPv4 static route

Router(config)#ip route 0.0.0.0 0.0.0.0 <output_interface>

IPv6 Route static