An administrator is enabling IPv6-to-IPv4 communication for workloads hosted in an NSX environment. The workloads use IPv6-only addressing, but the…

NAT64 in VMware NSX is a stateful translation service that enables communication between IPv6-only and IPv4-only networks. It is supported on both Tier-0 and Tier-1 gateways. A key requirement for its implementation is that the gateway (either Tier-0 or Tier-1) where NAT64 is configured must be in an active-standby High Availability (HA) mode. This is because NAT64 is a centralized service hosted on the Services Router (SR) component of the gateway, which operates in an active-standby configuration to maintain translation state consistently.

A. NAT64 is a stateful translation mechanism, not stateless. It must maintain a session table to map IPv6 addresses and ports to their IPv4 counterparts for the duration of a connection.

C. NAT64 is supported on both Tier-0 and Tier-1 gateways, providing flexibility for different network topology designs, not just on Tier-1 gateways.

E. NAT64 requires the gateway to be in active-standby mode to ensure state consistency. Active-active mode is not supported for this specific service.

1. VMware NSX 4.1 Documentation

NSX Administration Guide

"NAT64" section.

Reference for B & E: "NAT64 is a centralized service. For a Tier-0 gateway

the service is hosted on a SR (Services Router) in active-standby HA mode. For a Tier-1 gateway

the service is hosted on a SR in active-standby HA mode." This confirms the active-standby requirement for both gateway types.

Reference for C & D: "You can configure NAT64 rules on Tier-0 and Tier-1 gateways." This confirms support on both gateway tiers.

Reference for A: The document describes NAT64 as a translation mechanism that "allows IPv6-only clients to contact IPv4-only servers

" which inherently requires stateful connection tracking

a core principle of NAT. The active-standby requirement also points to the need to synchronize state

which is a characteristic of stateful services.