First post, by criver
Here I'll explain how to set up multiplayer for jurassic war (many thanks to h-a-l-9000 for helping me set up the modem mode):
First you have to start DOSBox 0.74 Options.bat - find [serial] and make serial1=nullmodem (you can choose serial2/3/4 if it doesn't work with 1).
Do the same but serial1=nullmodem server:192.168.1.100 (this 192.168.1.100 should actually be the server ip - so check the ip of your pc that runs as server and write it rather than 192.168.1.100).
Next run the game on both PCs, go to multiplayer game in the menu and then to Com setting (multiplayer game -> com setting). The baudrates on both PCs should be the same (I think that with a higher baudrate the game runs faster - at least it was like this for me). The com ports should also be the same on both pcs and they should match the serial (if you chose to write serial1=nullmodem in dosbox you should use com port 1 if you wrote serial2 =nullmodem then you should use port 2).
After all of this just click on Null Modem and play (Multiplayer game->null modem).
First you have to start DOSBox 0.74 Options.bat - find [serial] and make serial1=modem (you can choose serial2/3/4 if it doesn't work with 1).
Run DosBox and write loadfix (a lot of thanks to hal-9000 for pointing out that I should run loadfix before trying modem). Run the game. After that go to multiplayer game-> com setting. Do the same changes in com setting as for null modem.
Go to multiplayer game->modem and press recieve.
Go to multiplayer game->modem and write the IP of the server in Phone No - choose that phone no and press dialing.
P.S. You might want to turn off your firewall before trying this. And I
know the game is extremely slow in multiplayer (even in LAN) - I don't know how to fix that - it doesn't run fast enough with null modem or modem to be playable. If you know how to make it run faster I'd be happy to know.