is port forwarding enabled?

Thanks and I apologize as well, but the way customer service explained it to me is that the modems they use was not built with those options and a router gives you access to those options and on the times it doesn’t, it kind of tricks the modem. 
he told me that everything I need to set up, do it with the router… I was skeptical as well but it looks like it opens the ps4 ports for playing and a couple of them it wouldn’t due to security.