Change a DSL router from No-NAT to NAT

Posted on 2001-07-12
Last Modified: 2008-02-01
Is it possible to change a router from No-NAT to NAT without an engineer coming round?  We have 16 allocated IP addresses, and our network needs more.  We are not worried about VPN or anything.
It costs loads to get an engineer, so I wondered if anyone knew how to do it.
Thanks in advance
Question by:MitchBroadhead
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LVL 11

Expert Comment

ID: 6277920
What kind of DSL router?

Author Comment

ID: 6277952
it was installed by BT (British Telecom).
They say they use Alcatel routers, but there is no info on the router itself (Except bt logo).
Do all routers nowadays support NAT, or will they have to install another one?

Author Comment

ID: 6277965
it says they use alcatel or fujitsu modems
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LVL 11

Expert Comment

ID: 6278115
The Fujitsu is a stupid device.  It basically acts as a bridge.  No NAT.

Accepted Solution

svindler earned 100 total points
ID: 6280241
Have one of your existing machines with a public address act as a proxy server for the private addresses you use.

Expert Comment

ID: 6326717
The Alcatel is one of the models used by Bell South for their DSL hookups.  The configuation is apssword protected and the last one I looked at was locked by the carrier.

The Alcatel is a very nice device, it is very much like the Linksys devices that support NAT, DHCP, and secure connections.

This is what you can do.  Get a Linsys cable modem router and put it between your Alcatel device and your network.

The Linsys device, once connected, you can use your web browser to connect to it via from the inside.  Read the book for the default password, I believe it is admin, and use NO user name.  It is a graphical interface and very straight forward.  Turn on DHCP, assign a starting address and the exact quantity of addresses you would like it to dish out.  You can make that as many as 253, but if you need some sort of security, you would allocate just as many as you will need.
There is a lot to a Linsys cable modem router, so read the book, it's an easy read.  There are many types of Linsys cable modem routers, so look at them all before you buy one. They have 2.4 ghz wireless devices with a print server built-in, and they have every everything from one port out, to 4, or even 8 10/100 switched ports out.  In other words, you can improve the performence of your network by utilizing one of the switched port devices over the satndard $80 one port Linsys.  You can accomplish the same NAT, and DHCP services for your network with all of them, the only gain in the multiport devices is the improved through-put between the switched ports.

You will only need one address from your Acatel modem to do this.  You will only need outside support if you have no idea about what you are doing.  Linksys has toll free tech support, and web support.

I hope this helps..   Also, Bell South told me that they would come out to configure the Acatel, but they would bill us for it, and they would not tell us the password because the device can handle rather large networks if it is programmed correctly. They want to bill the customer if they put a larger number of users on the device.

                  Joe Massimino
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Expert Comment

ID: 7803486
This question appears to be abandoned. I will allow one week before I close this question
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Author Comment

ID: 7815264
Svindler: this is what i did in the end, using NAT32 to share the network connection after adding a second network card.  Then I got concerned about the security risks involved in having one of the machines accessible from the internet, especially due to the new port 445 netbios hack.  So I installed an old pentium pro machine with a redhat linux kernel and installed a NAT firewall with iptables to act as the router.  This is now much safer and allows me to tunnel through to all the machines using port forwarding on my firewall.  Now I can VNC support all the machines and i don't even have to go to the office as much.  Good job i didn't get a NAT router in the end!

Expert Comment

ID: 7820407
Please be aware that VNC in itself is NOT secure, as the password and data are passed in the clear unless you tunnel it using ssl.

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