Cisco IOS Network Address Translation Overview
Here is a great article I found online. It is a very good overview of what NAT is and how to make some sense of it.
Cisco IOS Network Address Translation
Basic Router Setup
Thank you for your Question. So a basic setup to get you going and to get all 5 of your computers online you will need a DHCP and NAT. The nice thing is you will only need to configure the Router. I have created from your email what I think is the network you currently have.
So to configure the router we have to do a couple of things.
- Setup Port on Router for DHCP from Modem
- Setup DHCP Server on Router
- Setup Nat
To get started console in to the Router, and get in to Config mode.
Router> en
Router# Conf T
Router(config)#
Then let’s run some commands.
Hostname YourNameHere
Ip dhcp pool Pool1
Network 192.168.100.0 255.255.255.0
Default-router 192.168.100.1
Dns-server 4.2.2.1 4.2.2.2
You now have a DHCP Server running on your router. Time to configure the ports.
interface fa0/0
description External connection to Modem
ip address DHCP
ip nat outside
ip nat enable
ip virtual-reassembly
duplex auto
speed auto
interface fa0/1
description internal
ip address 192.168.100.1 255.255.255.0
ip nat inside
ip nat enable
ip virtual-reassembly
duplex auto
speed auto
So your ports are now configured. As long as your Modem is providing a DHCP address to the router you should be good to go. There are still a few more things we will have to do to get this up and running.
ip default-gateway fa0/0
ip classless
ip route 0.0.0.0 0.0.0.0 fa0/0
ip nat inside source list 7 interface fa0/0 overload
That’s it. You should be good to go.
Cisco AAA login authentication with Radius (MS IAS)
This document will give you the bare minimum to provide RADIUS authentication to your Cisco Devices using Microsoft Internet Authentication Service (IAS) RADIUS server. Using RADIUS on your Microsoft server to authenticate Cisco devices allows you to use the same usernames and passwords on your Windows servers and Cisco devices. Video coming soon.
Steps
1) Install IAS
2) Configure IAS
3) Configure Cisco Device
4) Test
=========================================
1) Install IAS
=========================================
Click "Start > Control Panel > Add & Remove Programs"
Click "Add/Remove Windows Components"
Double-Click "Networking Services"
Select "Internet Authentication Service"
Click "Ok" (DO NOT Uncheck any of the Other Items. This will Unistall them from your Server)
=========================================
2) Configure IAS
=========================================
Click "Start>Programs>Administrative Tools>Internet Authentication Service"
*** Create Remote access Policy *** (left Pane)
Select "Remote Access Policies"
(right pane) Delete all policies
(right pane) Right-Click and Select "New Remote Access Policy"
Click "Next" Select "Set up a custom policy" and give it a name
Click "Next"
Click "Add"
Select "Windows Groups"
Click "Add" Type "Domain Admins" (or any other group you would like to use)
Click "Ok"
Click "Next"
Select "Grant remote access permission"
Click "Next"
Click "Edit Profile"
Select the "Authentication" tab
Select "Unencrypted Authentication" only
Select the "Advanced" tab
Change the service-type from "framed" to "login"
Delete "Framed-Protocol" Click "Add"
Select "Vendor Specific" Click "Add"
Select "Cisco" from the drop-down box
Select "Yes. It conforms" Click "Configure Attribute"
Change Attribute Number to "1"
Set the Attribute Format to "String"
Type "shell:priv-lvl=15" in the Attribute Value field
Click "Ok"
Click "Ok"
Click "Close"
If you get an error, select yes or no …. it doesn’t matter.
Click "Next"
Click "Finish"
*** Add Radius Clients ***
(Left Pane) Click "RADIUS Clients"
(Right Pane) Right-Click and click "New Radius Client"
Give the client a friendly name and enter the ip address
Click "Next"
Enter a shared secret password
Click "Finish"
=========================================
3) Configure Cisco Device
=========================================
*** IOS Configuration ***
aaa new-model
radius-server host 192.168.10.100 key P@ssw0rd
ip radius source-interface f0/0
aaa authentication login default group radius
local line vty 0 4
login authentication default
*** PIX Configuration ***
username blindhog password Raz0rb4ck
aaa-server RADIUS (inside) host 192.168.10.100 P@ssw0rd
aaa-server LOCAL protocol local
aaa authentication ssh console RADIUS LOCAL
aaa authentication telnet console RADIUS LOCAL
How to Console to a Cisco Device
How to Console. A Quick little video on how to setup a connection via the console on a Cisco Device. This is one of the fastest ways to connect to a New cisco Device to allow you to start the configuration process.
Steps:
-
Open Hyper Term
-
File > New Connection
-
Name the Connection I went with Cisco.
-
Optional - Change the Icon, if you want to save the connection - recommened.
-
Select Com1 (my Serial port) yours might be different.Settings for the connection:
- 9600 bps
- 8 bits
- none
- 1 stopbit
- no flow control
-
Click OK and you are done
-
You if the device is on hit "enter" to get a command line.

