Configuring a router to act as an ISP

PACKET TRACER ISP

Overview:  Configure a Router to act as an ISP

Difficulty: Easy
Objective: To have a router acting like an ISP for upcoming Lab Setup

I. ISP CONFIGURATION STAGE

<Configs>

First we will assign a hostname to our ISP Router

hostname ISP

Then we will create a loopback addresses to simulate the Public IP Address of the site were going to access

interface Loopback 1
description Global DNS
ip address 4.2.2.2  255.255.255.255

interface Loopback 2
description Google DNS
ip address 8.8.8.8  255.255.255.255

interface Loopback 3
description google.com
ip address 8.8.8.1 255.255.255.255

interface Loopback 4
description yahoo.com
ip address 98.139.183.24 255.255.255.255

We will then Assign IP Addresses to our interfaces

interface FastEthernet0/0
description ***Link to R1***
ip address 77.77.77.1  255.255.255.252
duplex auto
speed auto

interface FastEthernet0/1
ip address 2.2.2.1  255.255.255.252
duplex auto
speed auto

Then we will route it via EIGRP

router eigrp 1
network 77.77.77.0 0.0.0.3
network 2.2.2.0 0.0.0.3
network 8.8.8.8 0.0.0.0
network 8.8.8.1 0.0.0.0
network 98.139.183.24 0.0.0.0

Now were going to create an access-list to prevent entry of Private Addresses to our ISP Router

ip access-list standard BLOCKED
deny 10.0.0.0  0.255.255.255
deny 172.0.0.0  0.255.255.255
deny 192.0.0.0  0.255.255.255
permit any

Put this command under interface fastehernet 0/0 to filter those addresses

ip access-group BLOCKED in

II. Configuring a DNS Server for the ISP

Assign this IP Address to your Server.

IP

Then Configure the Server as follow.

Perform a Ping test to verify connectivity.

PINGPING