how to get Server Real IP with port

Hi, I am developing a redirect payment method plugin where I need to send server remote address with specific port number to request them. Can anyone suggest me the suitable way?
TIA

Do you need to send the client IP Address or the IP address of the server?

You can use https://docs.microsoft.com/en-us/dotnet/api/system.net.networkinformation.networkinterface.getallnetworkinterfaces?view=netframework-4.8 to find information about server IP.

Since it is payment plugin, usually you need client's IP. It is a bit tricky because your customer might be behind a proxy. You can try https://gist.github.com/jjxtra/3b240b31a1ed3ad783a7dcdb6df12c36 code snippet.