If UPnP is on in your router, turn it OFF. With UPnP enabled, IP cameras reach out to your router and open ports to themselves, which is a terrible plan because 1) you don't know it is happening, 2) you don't know which ports are being opened, 3) most IP cameras are insecure as all hell so once they are open to the world like this, their vulnerabilities are easily exploited and an attacker has full access to the camera video or even your entire home network.
OpenVPN is one of the more secure options, but most routers don't have a server for this straight out of the box, and most devices don't have a built-in client (you'd need to download it). The simplest option is PPTP vpn, which your router may support already, and every modern computer or smart phone can connect to.