It should put you on the server you last logged on to If it's sending you to smp4 everytime then something isn't working right
I'm also curious why the only server i can log on with a ip is smp4... All others give me a server error
It automatically logs new players onto the recommenced server, which is currently smp4 I have no idea why it logs you on to that one though, unless you're logging off while on smp4 of course