open fire has limit of simultaneous connections or not? in windows xp I noticed only the possibility of 25 connections in linux it would have this limit still or she would be limitless the connections?
There is no real connection limit (*), independent from your operating system. It is only limited by hardware requirements. There are some reference values.
(*) Probably they are using integers to store the connection count, so there should be a limit at 2^31 > 2,000,000,000 connections