First of all, you will need your Modem (ISP´s device) and an additional router (my modem acts like a router too), there is no need to port forwarding. *Recommendations at the end* Background: When I connected two ps4 to the same network (Modem) I got a lot of errors in both devices while playing multiplayer competitive and even vanguard activities. I got Baboon, Beaver, Quail, Marionberry, Weasel, Anteater, Bee, Elderberry, Camel, Canary, Centipede and Viper. Most of them networking issues, also I had Nat type 2 in one PS4 but in the other one i had Nat type 3, never type 2 in both. So I started to play with my network settings. Nowadays this is my network configuration: My router is connected to my Modem normally (no like a bridge). One PS4 is connected via WiFi to the modem and the other one to the Router via Ethernet cable. Both PS4 (WiFi to Modem and Ethernet to Router) configuration [PC Settings]: 1.- Set IP as static (AKA Reserve IP). 2.- Activate DMZ for the PS4 (nomally located in Firewall Settings). Do these steps in the Modem/Router configuration (in your PC). Both PS4 (WiFi to Modem and Ethernet to Router) configuration [PS4 Settings]: 1.- Go to Settings->Network->Set up Internet Connection. 2.- Select Wi-Fi or LAN Cable, as the case may be. 2.1.- [If Wi-fi] select your network (if invisible go to the last option) 3.- Select Custom,then on IP Address Settings->Manual 3.1.- IP Addres: write the IP you reserved before. 3.2.- Subnet Mask: 255.255.255.0 3.3.- Default Gateway: The URL you used to configure your network in the PC (e.g. 192.168.0.1). Note: Are different for each PS4 3.4.- Primary DNS: 8.8.8.8 (Google DNS) 3.5.- Secondary DNS: 8.8.4.4 (Google DNS) 3.6.- Select Next 4.- MTU Settings -> Automatic 5.- Proxy Server -> Do Not Use Recommendations: 1.- Router / Modem settings are changed from your computer. [Visit: https://www.timewarnercable.com/en/support/faqs/faqs-internet/homewifi/how-do-i-change-my-wifi-settings1.html ] 2.- Avoid congesting the network. Turn off Wi-Fi of other devices while you are not using them, otherwise you will get Beaver error. 3.- To solve Marionberry error you should turn off your PS4 and unplug the AC cable for 1 minute. Then turn on and play normally. If this solution doesn't work reset your Modem (and Router, as the case may be). 4.- While playing competitive (crucible), don't check the other players (don't press option button), otherwise you will get quail. 5.- If you get an error (Beaver or Quail) and you don't want to turn off your PS4 or reboot your Modem/Router you can go to a social area (Tower, Patrol, etc) and wait until other players appear (Not always work, you should wait more than 4 minutes). 6.- Set major priority to your PS4 in your Modem/Router settings [QoS] Feel free to feedback. *sorry for my english*