I study the document about SIM and use sample code, but the following still make me confuse.
if the end user is under NAT and the ip address is not a public ip address, can SIM work well?
the topology like this
end user -----(DEVICE server)-----(ROUTER)-------INTERNET--------(Authorize.Net payment gateway)
When I use Relay Response, does Autorize.Net payment gateway create a new session to Relay URL?