Update vpn-gateway-faq-nat-include.md

Added information on NAT rules in active-active gateways where a separate rules need to be created for separate gateway instances

Author: Emanuel Santos

includes/vpn-gateway-faq-nat-include.md

@@ -32,6 +32,8 @@ Only static 1:1 NAT and Dynamic NAT are supported. NAT64 is NOT supported.
 ### Does NAT work on active-active VPN gateways?
 
 Yes. NAT works on both active-active and active-standby VPN gateways.
+Bear in mind that each NAT rule is applied to a single instance of the VPN gateway.
+In active-active gateways create a seperate NAT rule for each gateway instance through the "IP configuration ID" field.
 
 ### Does NAT work with BGP connections?