Nat

Short for Network Address Translation, an Internet standard that enables a local-area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations.

NAT serves three main purposes:

Provides a type of firewall by hiding internal IP addresses
Enables a company to use more internal IP addresses. Since they're used internally only, there's no possibility of conflict with IP addresses used by other companies and organizations.
Allows a company to combine multiple ISDN connections into a single Internet connection

 

Check out NAT on www.howstuffworks.com

Your router/firewall assigns different IP ports to each machine on your network but the same IP address is used for all the machines (on the internet side).

 

Kevin, that's a cracking site

Also very interesting is the link to Shields Up! to probe one's ports

 

I ran that shields up - absolutely everthing came back as stealth mode - I have an alcatel speed touch 570 adsl router - it has a built in wireless base station and a FIREWALL !! works a treat.

 

Shields Up is indeed useful, although there's quite a few folk out there who question Steve Gibson's work...

http://grcsucks.com/

 

Stu200 - with NAT enabled only tcp/udp ports you configure are allowed to initiate from outside to inside.

However, if you're initiating from inside to outside then I guess everything is allowed by default.

You should always run something to protect you from downloading trojans, or check regularly yourself. NAT stops anyone port-scanning you, but not abusing a connection you initiated

Richard

Richard

 

Mornin' all,

Having just moved to ADSL from the land of dial-up, I'm trying to understand what I need to change on my little network. I've got a router with NAT enabled (and NO port forwarding set up yet) which I understand acts as a "kind of" firewall between my LAN and the Internet.

As I thought I understood it, to make any server on my LAN available to the outside world, I'd have to configure port forwarding to pass through to a particular machine ... but, I fired up Audiogalaxy satellite (an MP3 file-sharing thingummy) and it's been working fine all day I'm guessing my understanding's flawed, so can anyone enlighten me ?

The main reason that I ask is that I'd believed I could now do away with having to run ZoneAlarm on all the machines on the LAN, as the NAT would take care of it, but if it isn't, I'll have to rethink the strategy.


[Edited by stu200 - 2/10/2002 3:23:01 AM]