Leased Line & PA addresses

This is the simplest of all the configurations. This example is for someone who has a leased line to the ISP and PA addresses from the ISP. PA space is a block of public addresses that comes from your ISP and belong to their address block. The PA stands for Provider Associated. This is usually a small block of 8-32 addresses for public servers like Web, Mail or VPN servers as well as a Firewall to protect your internal networks. To get these block you will have to justify them to your local internet address registry, but your ISP should sort this out for you.

Information Needed

From You
router                                              The hostname of your router
cisco                                               The password for telneting to your router
ciscoen                                            The password for enable access to your router

From your ISP
172.16.1.1, 172.16.1.2                   The DNS servers on your ISP’s network
172.16.1.0 255.255.255.252          This is the subnet that you use to connect on your leased line
172.16.10.8 255.255.255.248        These are the addresses for your public servers

Sample Configuration

service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname router
!
enable secret ciscoen
!
ip subnet-zero
no ip source-route
!
no ip bootp server
!
interface Ethernet0
description === Your Public Network ===
ip address 172.16.10.9 255.255.255.248
no cdp enable
!
interface Serial0
description === Leased Line to ISP ===
ip address 172.16.1.2 255.255.255.252
no shutdown
no cdp enable
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.16.1.1
no ip http server
!
access-list 1 permit ip 172.16.10.8 0.0.0.7
no cdp run
!
line con 0
line aux 0
line vty 0 4
access-class 1 in
session-timeout 35791
password cisco
login
!
end

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