Hi User,
Welcome to the site and to WinMX.
I wish there was a real simple answer to your question but there isnt so Im going to explain best I can for you, and try not to confuse you too badly.
"Can someone see my IP if they are uploading or browsing my files?"
Any time you have an active transfer or direct connection to someone they are 'able' to get your IP. This is true for secondary or primary users. It does require that person knows 'how' to get that information and has tools installed to do so, however they are readily available and in all my years on WinMX I've not seen too many users that have had problems related to this.
If you use a primary connection it is also possible to gain your IP address from a Whois or Browse. WinMX has to know your IP address to direct traffic to and from you and it keeps this info in HEX, which can be seen on the Whoise or Browse Title bar.
Again this has never created any real issues to my knowledge.
"Does WinMX have a central server?"
No WinMX is completely Decentralized. The only part of WinMX that does utilize a central server are the OpenNap servers. Here is a page about the way WinMX Peer Network works:
https://www.winmxworld.com/tutorials/wpn.htmlTechnically its entirely possible for the RIAA or Movie Industry to find an IP of a sharer yes.. however, to date they are not monitoring WinMX in this way. Because of the Decentralized system in place it would be very difficult for them to prove beyond a doubt that said traffic was coming from an IP address. More importantly to note on this subject is 'what are they going to do with just an IP?' The same they have been doing and the courts are finally putting a halt to.. John Doe Lawsuits. Just because they have an IP address doesnt mean they have any information about the account holder or the actual PC user. Because there are still laws that prevent ISPs from giving out that information without a actual warrent and for a warrent to be served there has to be names and proof of something..
Some ISPs are more RIAA friendly and have suffered class action suits against them for releasing information about account holders without said account holders permission.
You may have heard about some of the ppl that have recieved letters from thier ISP. This is a fishing expedition and unless you respond to that letter you've made no admissions of anything and given no permsisions to the ISP to release your infomation to anyone, period.
Its also worth a mention here that to date not one John Doe Lawsuit has been proven or made on users of WinMX for use of WinMX. Not one person has recieved one of those letters that Im aware of in all my years here for using WinMX.
I hope this puts your mind at ease a bit, if not just post any questions you have here, we're always glad to help any way we can with the facts as we know them.