How do you get two computers to connect after launching multiplayer magic carpet. Has anyone successfully done it?

bump

I haven't tried, so I don't know how much work it will be (assuming it is still possible). Assuming it is, then you'll probably have to do things like open ports, and get DosBox to connect with another computer's DosBox remotely.

Maybe check the DosBox site, and see if there is something there that can help?

Back in the day, I remember from a magazine stating that Novell NetWare is required for multiplayer, which is a very unusual requirement indeed.
To quote from the dosbox.com comments:
Works. Needs Netbios though (and IPXNET - edit the DOSBOX.cfg file). Also needs to start with 'carpet.exe -network'.

I created a batch file carpet.bat like this (ignore anything in brackets)

@echo off
cls
ipxnet connect 192.168.0.??? (server to connect to)
ipxnet startserver (in case it doesnt start a server)
c:\novell\nios\netbios.exe (wherever you put netbios)
carpet.exe -network

Souce: https://www.dosbox.com/comp_list.php?showID=712&letter=M