User limit

Hi

We are testing Openfire 3.71.

I have a question.

How many concurrent client connections can support openfire?

I say concurrent connection because we set 10 mins. to logoff inactive users.

The problem is hardware requeriments or Openfire have limit?

For example, we have 50.000.000 users but only 3.000.000 are connected at same time.

Wich machine type we need to support this?

Thanks

Miguel