Network Address Translation (NAT)

[ElijahBaley]

Hello,

I have configured my test server with 2 NICS, one will connect to my LAN and the other is connected to my Cable Modem.

I would like to set-up Network Address Translation so that I can offer internet connectivity to all clients on the private LAN, however.. the cable modem receives a dynamic address from the ISP, (although, I think that it does not change often) so is it possible to set this up just using the features of W2k Server without additional hardware?

(What other options are their to make better use of my dynamically assigned internet connection)

Thanks for any help,

 

[MattWray]

NAT should work fine with that setup. You specify interfaces in RRAS, not actual IP's. Just ensure your "Internal" interface is static and does not have a gateway. You may also have to add a static route with dest 0.0.0.0 and mask 0.0.0.0 to use your "External" interface.

Thanks,

Matt Wray

http://www.total-tec.com

http://www.sss-steel.com

 

[ElijahBaley]

Thanks Matt,

I will check it out at the weekend, although I think that I have to assign a pool of IP addresses to translate to on the public Internet - if I have to watch/change/refresh the Dynamic one, that what I will do (just testing)

Routing will have to take place, so I may have to put that default route in, but I wonder if this is taken care of by NAT?

Cheeers

 

[MattWray]

With my experiences, NAT isn't trustworthy to route, I always set up a static route in RRAS. You will need to set up a scope of addresses for your LAN, like a 192.168.1.x type setup. As long as you have your External NIC set to Obtain an IP address automatically, you will not have to watch that...
Good Luck!

Thanks,

Matt Wray

http://www.total-tec.com

http://www.sss-steel.com

 

[ElijahBaley]

I already have DHCP handing out addresses in the 172.16.0.10 - 172.16.0.254 range, the server IP is 172.16.0.1, I assume that the clients should treat the server as the default gateway and point DNS requests to the local DNS server as well (172.16.0.1)

this is where I get confused.. do I need to disable DHCP and configure NAT to assign the local addresses on the private LAN instead? or should it work as above?

Thanks for your help

 

[MattWray]

You do not have to disable the DHCP scope. Instead, set up Routing and Remote Access to make your Win machine a network router. Set up NAT and a default route and you'll be good to go. I actually had a network where this was implemented and it worked fine, other than when the server needed to be rebooted....

Thanks,

Matt Wray

http://www.total-tec.com

http://www.sss-steel.com

 

[dogbert2]

A better way to do this is to use a router which supports cable modem/DSL connection that has the ability to do NAT and DHCP in it (cisco 806/831 comes to mind here).

It's better to have a piece of hardware do this for you rather than make a NT/win2k/unix/linux box do this for you, since once the router is powered up, you don't have to worry about GUI, hard drives, or something else causing your NAT/DHCP to stop working.

Just my 2 cents