[nradov]

There is nothing illegal about purchasing hardware products from those companies and then selling them on to other customers, even without a formal sales agreement in place. This is the first sale doctrine. However software is different and licenses can't necessarily be resold.

[ghaff]

And, of course, many hardware products do have software components these days. But, yes, in general you can resell hardware without a formal agreement. You just can't claim to be an authorized partner or reseller given that implies certain training levels, etc.