(05-07-2022, 02:13 AM)Ahmed Sayed Wrote:Quote:Sorry, I can't answer that.
Why?
Because I don't have an answer to provide. I've personally never needed to punch a hole between 2 NATs, so I can't explain to you how to implement it in practice. Even without using Indy, using just plain socket APIs, it is still difficult to implement by hand. There are technical documents floating around that explain the theory.
(05-07-2022, 02:13 AM)Ahmed Sayed Wrote: At least can you tell me how to query the public port using Indy TCP components?
There is no standard protocol to perform that query, and certainly nothing built-in to Indy to perform it. It is the responsibility of the NAT router to publish it somewhere, such as on a webpage, or a uPNP endpoint, or somewhere else that an app can access programmably. A better option is if your own code is opening the public port to begin with, ie via uPNP, then you will know the port up front and there is nothing to query. But Indy has no uPNP components, so you will have to use platform-specific APIs for that, or 3rd party uPNP libraries.