I have read on the Draytek Website that the Vigor 120 ADSL modem can pass on a single public IP address to a router that sits behind it like a Vigor 2955.

My network consultant insists that I need 2 public IP addresses to use this configuration. I only have 1 Public IP address; is it possible to use the Draytek 2955 behind an ADSL modem as I interpretted or not?

Thanks,

Colin

The V120 will indeed pass on the specific IP address to the PPPoE device that sits next in line. There is no actual requirement to allocate an IP address to the V120 itself, except for configuration and monitoring uses. This could be a private address such as the default 192.168.2.1 and the ethernet interface on the PPPoE router could be 192.168.2.2. This does not affect the allocation of the external public IP address.

If you also have a routed subnet coming in with your ADSL service, the PPPoE router can distribute this to the clients behind it as it sees fit.

So, while I think the whole are can be confusing, the answer is No, you only need a single public address if the PPPoE router is going to use NAT to service its clients.

If however, you intend to run a public web server behind the router, you will also need a routed block of addresses from your ISP, UNLESS you pin port 80 on the public address to a specific NAT'd client behind the router.

Does this cover the question asked?

Yes thank you, Kelvin.