One-to-One NAT environments allow you to perform both SNAT and DNAT for all machines provisioned behind and NSX Edge Gateway. For each machine provisioned onto the One-to-One NAT network an External IP is added to the Edge gateway for the NAT translation. The External IP is assigned from the External Network Profile that is assigned to the One-to One NAT Network Profile. Although the One-To-One NAT network will use NAT translation to communicate with the upstream networks (North – South) it is routed to other networks connected to the same NSX Edge Gateway. When deploying a multi-tier application that has multiple network tiers attached to an NSX Edge Gateway all the back-end networks are routable so it’s important no to re-use IP space across different Network Profiles.
In the below diagram there are three Multi-Machine apps. Each one has three web servers, two app servers, and two database servers. The database servers are on a private network, no NAT translation to the upstream networks. The App servers are using a One-to-Many NAT network where they are using SNAT to get access to the upstream network, and the Web Servers are using DNAT for both inbound and outbound traffic. You will notice that each of the Multi-Machine Apps are using the same Up address on the backend, however the IP’s assigned to the NSX Edge Gateway’s external interfaces are different. Notice for the One-to-One NAT that there is an equal number of external IP address. Lao notice in this scenario where we are using both One-to-One and One-To Many the external IP’s are on the same subnet. They all should come from the same External Network Profile that the related to the network that the NSX Edge Uplink interface is provisioned to.
Creating One-to-One Network Profiles
1. Navigate to Infrastructure –> Reservations –> Network Profiles and hover over New Network Profile and select NAT.
2. Assign a Name then select the appropriate External Network Profile for the external interface of the NSX Edge. Next choose One-to-One as the NAT Type and assign the subnet mask (Mine is grayed out because I’m in edit not create) and default gateway, then select the IP Ranges Tab.
3. Select New Network Range and assign a name and a starting and ending IP address then select OK. Select OK to save the One-to-One Network Profile.