If you are thinking of using your home computer to host a server GTFO N00B!
If however your using a (vps/dedicated server/anything in a data center) the port is already in use, so you may have to use a different port example: 25555
If you are considering hosting a gay hamachii server or one of your home connection you have been warned. Hachachii let's people like me have unfiltered access to your LAN, With that I could easily steal all your information, install a rat or 2, or possibly just delete your win32 for shitz and giggle's. That or real server owner's the ones who learned fucking linux to host this shit and pay hundreds of dollar's a month can take your internet out for 2-3 hour's at a time. My booter last's only 10 minutes at one time but it is strong enough to take down any server with dos/ddos protection. (ie yahoo.com, barrackobama.com, shit like that.