How to configure interfaces on a router

1. Ethernet interfaces [ip address and no shut]

2. WAN interfaces, important to remember the clock rate on DCE ends

   1. show controllers s0/0 is a good way to find out if the end is DCE

   2. ip address, no shut and clock rate

Base Cisco IOS commands

enable

Config t

hostname Router5

enable secret class

enable password cisco

!——————-

line vty 0 4

password cisco

login

!————-

line con 0

logging sync !*****very important*******

no exec-time !*****very important*******

password cisco

login

!————-

line aux 0

password cisco

login

!————-

no ip domain-lookup

Theses can be copied and pasted to each router you want to configure.

What is telnet ?

While being one of the most unsecure protocols, due to it’s transfer of passwords in cleatext, this is one of the most useful and widely used protocols/applications.

How can you connect to a router using Telnet ?

First you need to configure the router to accept telnet logins by doing

line vty 0 4

password cisco

login

This will enable 5 simultaneous telnet logins to the router.

on smaller routers, configuration is accessed by connecting through a web browser. So telnet is not an option.

Cisco router bootup process as it happens in hardware.

1. POST – Power On Self Test

2. Depending on the config_reg parameters, locate the IOS in flash and boot.

3. Copy startup_config (NVRAM) to running_config (DRAM)

4. etc …

There are 5 types of passwords that can be configured on a router.

1. enable password [enable password cisco]
2. enable secret [enable secret class]
3. telnet [line vty 0 4, password cisco, login]
4. aux [line aux 0, password cisco, login]
5. console [line con 0, password cisco, login]

They all have the same syntax/ pattern.

The image is an easy way to remember how to configure passwords