LINK UP my vista and xp

[dflw king]

hello all, i am having trouble linking up my windows xp and my vista to play dflw i am using an ethernet cable from both comps into a neuf live box so i take it that i can use this as my network hub? if not what should i buy, and if i this is fine its still not working i have tryed using hamachi, opening the dflw ports i even maneged to do the protacall thing on xp computer then some 1 told me it that that idea wont work cos u cart do the protacall trick on vista and well is it posible or do i have to buy another computer if so should i buy a vista to have two vista's to link up or another xp. or can i keep both and maybe just buy a real hub. not sure what to do can some 1 help me please.......: