When is NAT not NAT? When it's a BT Business Hub?!

NeilHatton — Tue, 08 Jan 2013 21:38:40 GMT

Hi all.

can anyone settle this argument for me? On both a previous 2wire and now a Business Hub 3, I have tried to set up what I believe is the correct use and term for NAT, and it don't seem BT supports this correctly?

I have multiple static registered IPs in the 81. range. My internal private IP is 10. I want to keep my web accessible hosts on 10. addresses and have the Business Hub use one registered IP per server and fully translate from an 81. address to a 10. address per server. To me, the 2wire and the Business Hub have to make use of DHCP for such hosts, and ACTUALLY assign the servers the 81. addresses instead! Unless I am too old school, this is bridging such addresses
into the private LAN? Any 10. users then using these hosts internally, have to bounce off the router!

Can anyone settle this and confirm the two mentioned routers are incapable of doing my understanding of full NAT?

Best regards,

Neil

Re: When is NAT not NAT? When it's a BT Business Hub?!

adrianc — Wed, 09 Jan 2013 23:59:23 GMT

Hi Neil,

Yes, that is one way that NAT can be performed. And you are correct that the Business Hub can't be configured to do NAT like that.

If you use the Business Hub to set up the machines on the public IP addresses then then 81.x addresses will be accessible from the LAN as well as the Internet. It will still be doing NAT for any other machines on the LAN to be able to access the Internet.

Thinking about it though, unless you have a decent switch, LAN<->LAN traffic will always be bouncing off of the router regardless of what IP address the server has.

Adrian

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When is NAT not NAT? When it's a BT Business Hub?!

Re: When is NAT not NAT? When it's a BT Business Hub?!