Considering for Multiple Platforms in a Server

Ayone who's tried sharing text format files with someone using a UNIX file system when you're on a Windows system knows that problems occur in readbility. I'm writing a server program, and I was just hit with a problem: I'm writing the code on a Windows machine, but because projects like Mono are advancing rapidly, I've made it a console app with the intention of being able to have it run on any OS. There's also the fact that computers of any OS will be accessing this server. Do I need to take any of this into consideration when writing the server? I'm just not sure if the differences will have any effect at the level of HTTP/FTP requests and how the files are transferred over the network.