IP-Upsell or more commonly known as 1-to-1 NAT can be used to give subscribers the experience of a public IP address. This requires your upstream provider to delegate a small subnet for you to use. The upstream provider configures it's network such that this small subnet will be reached over your WAN (static) IP address.

To configure this scenario on the HSMX gateway a few things need to be done.

• define 1-to-1 subnet on WAN interface
• enable the subnet for IP-upsell use
• billing plans need to be adjusted

Traditionally a small IP range is handed out to the customer by upstream and the customer is responsible for notifying upstream about which IP address is being used by the gateway. In that case you only need to configure the small range, in this scenario we got a single static IP assigned and a small IP range from upstream. The single static IP address is used to forward and receive traffic with upstream, and upstream uses the single static IP to send down responses for 1:1 NAT IP range.

Browse to Network → >Network Configuration and add an WAN entry, select the Port, set the mode to Static and fill in the remaining details. Tick 'Use entire subnet' when you wish to use more than a single address. Beware that large 1:1 subnets take a lot of configuration processing.

The next step enabling the WAN subnet for 1-to-1 NAT usage by subscriber networks. Browse to Network → One 2 One NAT pool and check the subnet you desire to share.

Make sure your billing plans are configured to use IP-Upsell. Go to Billing → Billing plan and click to edit a billing plan. Then check the IP-upsell option half-way down the page under Network settings.

When we connect a subscriber client to the LAN port and identify ourselves using a IP Upsell enabled billing plan we notice the following when we examine traffic destined from the HSMX (on the first upstream hop). Notice traffic is actually coming from the 192.168.5.6(/29) as assigned by IP upsell to the subscriber device instead of the default-ip 192.168.4.2.