Internal Protocols and BGP in relation to NAT...

[jsingh7]

Hello, I'm new to Cisco Networking... My question is about using Internal Protocols (RIP, IGRP, OSPF) with NAT... and also using an External Protocol such as BGP with NAT.

In studying for my CCNP:Routing certification, I came across this...
"In order to connect your Private LAN to the Internet, you HAVE to use BGP, since it is an External Routing Protocol, or an EGP"
Now how much of that statement is true. I thought you could just use NAT if you were using RIP, IGRP, or OSPF... to connect your LAN to the Internet.?? Do you really HAVE to use BGP on the router that will connect your network to the Internet?

Secondly, do you still have to use NAT to connect your LAN to the Internet if you are running BGP? I'm sorry if these questions seem to be a bit unclear or 'weird'. I basically just want to know how to connect our Lab of 10 2500/2600 routers to the Internet so that I can ping one of them from a remote location. If you can answer any of these questions, I will be VERY thankful!!!

J.

 

[wybnormal]

internet---BGP--ISP---privateIP/real subnet----YourRouter---LAN - private IP

You dont need to worry about BGP unless you plan to be a real node on the internet like an ISP is. Or pressing business reasons to run it. Normally you will connect to the ISP by static route, RIP or OSPF and let them deal with the BGP issues.

RealIP---NAT---PrivateIP

Doesnt really have alot to do with routing protocols like RIP/OSPF and so on. It's for translating one IP range into another or into a group of IPs for sharing a single IP. Better known as overloading or PAT (port address translation)

there are whole books on this so dont be offended my lite answer

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[jsingh7]

Okay, So I don't need to configure BGP on my routers in the lab to connect to the Internet? Let's say we're running RIP, IGRP, or OSPF on my 10 routers. How do I connect my routers to the Internet so that I can ping them from home?

Let's say the assigned IP address from the ISP is 198.50.15.x and my Routers' IP Addresses are in the 172.16.10.x - 172.16.90.x Range. They are all running RIP or OSPF, so what do I have to do to connect them to the Internet?... Just run NAT to translate my group of IP's to the assigned IP Address from the ISP??? Do I have to configue NAT on ALL of my routers?

 

[wybnormal]

whatever the router that is the gateway router will run NAT.

internet--ISP--PublicIP/Gateway/NAT/privateIP---LAN/lab

I have links to some NAT docs that explain it well.

http://www.packetattack.com/cisco_documents.html

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[MelchiorKD]

BGP is a policy based routing protocol, it is like RIP in that it doesn't take any metrics into consideration. You would use it to connect to two ISP's at the same time, thus needing BGP to say.....'go to this ISP' or 'go to that ISP' based on the policies that are set up. For example, you can have several t1's out to the internet, but want e-business to use one pipe, browsing to use another, vpn to use another, etc, you would use BGP for that. NAT has to do with IP, not the routing protocol that carries IP