Cisco Router Configuration: Password, IPv4, IPv6, VLAN & SSH

Posted on Apr 6, 2025 in ICT Systems Engineering

Cisco Router Configuration

Remove Router Password

• Power off the router physically.
• Hold CTRL + Pause keys.
• Rommon1>confreg 0x2142
• Rommon2>reset
• Router>enable
• Router#copy startup-config running-config

Change Passwords

• (config)#config-register 0x2102
• (config)#exit
• Router#copy running-config startup-config
• Router#reload

Set Router Password

• (config)#enable secret (password)
• (config)#line console 0
• (config-line)#password (password)
• (config-line)#login
• (config-line)#exit
• (config)#line vty 0 4
• (config-line)#password (password)
• (config-line)#login
• (config.line)#exit
• (config)#service password-encryption

Save Configuration to TFTP Server

• Router#copy startup-config tftp
• router#copy startup-config tftp:(IP)(Mask)

Configure IPv4

• router>enable
• router#configure terminal
• (config)#hostname (name)
• (config)#interface f0/0
• (config-if)#ip address (IP) (Mask)
• (config-if)#description (According to the topology)
• (config-if)#no shutdown
• (config-if)#exit
• (config)#interface serial 0/0/0
• (config-if)#ip address (IP) (Mask)
• (config-if)#description (According to the topology)
• (config-if)#no shutdown
• (config-if)#exit

Static IPv4 Routing

• Router>enable
• Router#configure terminal
• (config)#ip route (IP) (Mask) (exit interface)

Configure IPv6

• Router>enable
• Router#configure terminal
• (config)#interface f0/0
• (config)#ipv6 address (IP) link-local
• (config-if)#ipv6 address (IP)(Prefix)
• (config-if)#description (According to the topology)
• (config-if)#no shutdown
• (config-if)#exit
• (config)#interface serial 0/0/0
• (config-if)#ipv6 address (IP)(Prefix)
• (config-if)#description (According to the topology)
• (Config-if)#no shutdown
• (config-if)# exit

IPv6 Routing

• Router>enable
• Router#configure terminal
• (config)#IPv6 route ::/0 (IP)

Configure VLAN on Switch

• switch>enable
• switch#configure terminal
• (config)#hostname (Name)
• (Config)#interface vlan 1
• (config-if)#ip address (IP)(Mask)
• (config-if)#no shutdown
• (config-if)#exit

SSH Configuration

• (config)#ip domain-name (name)
• (config)#crypto key generate rsa
• (config)#line vty 0 4
• (config-line)#transport input ssh
• (config-line)#login local
• (config-line)#exit
• (config)#username (User) secret (Password)

Banner MOTD

• (config)#banner motd #" "#

Subnet Masks