EmanuelePulciDoria wrote on 2020-04-01, 20:32:
That is very interesting indeed because when I tried it in Dosbox I have ever only tested on 127.0.0.1 with 2 instances of Dosbox open at the same time with the nullmodem connection. I thought if it did not work in such a simple way it would have never worked on a connection with a computer behind a router...
I want to try now in both ways: with UnipCemu (I have to install everything though) and in Dosbox going outside of my local network (but for this I have to resolve port forwarding yet). Again as said I am just learning now about all these things.
Have you ever tried the nullmodem connection in Dosbox running as you said outside of your local LAN?
Well, I was primarily testing with UniPCemu, as using the Visual Studio debugger, I could actually see what bytes were being sent and received(although not both at the same time, due to the weird kind of packets used by 688 attack sub). One client kept sending the same byte eventually and the same kind of behaviour(with 0xAA bytes being received until disconnect) on the receiving side. When doing it over the internet, it immediately connected once the attempt was made, due to valid data being received instead of one unchanging value over and over again(which upon debugging the sender and receiver seperately I found out that what was being sent over the TCP connection wasn't what was received at all. E.g. 0x55 being sent and 0xAA being received, or another data entirely(I remember it sending some kind of 6-byte packet of sorts, with it having transformed into only 0xAA bytes at the receiver's side)).
Edit: OK. What was being sent and received was completely different from what I remember. See: Re: Hayes compatible modem emulation issues?
That explains exactly what happened with the two UniPCemu clients connected using a TCP connection through the Microsoft Loopback Adapter.
Btw, the nullmodem I haven't messed around with, as UniPCemu only supports a normal serial modem(dosbox's case: the modem option) connection instead of nullmodem(which is entitely different) cable emulation.