OpenPop.NET POP3 Library Documentation

MessageHeader.ReturnPath Property

A single RfcMailAddress with no username inside.
This is a trace header field, that should be in all messages.
Replies should be sent to this address.

a null reference if no Return-Path header field was present in the message

public RfcMailAddress ReturnPath { public get; private set; }

See Also

MessageHeader Class | OpenPop.Mime.Header Namespace