Some unknown internet providers might give you shared ip address they are part of CG-NAT usually badly configured network. Shared ip means you share this ip with hundreds of people. That’s where network conflict starts usually. . It will give you unnecessary firewall. This will make your internet almost unusable. The main reason they’ll give you shared ip because. Providers want to save Static ip address for future because they are running out of them. Still not sure if it’s 100% true or not. If you under CG-NAT
You will not be able to play games properly. Other people might not join your rooms inside the game or get error messages. Cameras will not work printers web servers . Many devices and other horrible things.
You can fix this by getting static ip address. Call your ISP and ask them to provide one. Pay if you have to usually it’s free.
If they can’t do that ask them for dynamic ip they might have If they can’t give you dynamic ip or static. You pretty much doomed. You can try asking them to put your existing router in bridge mode. This way you can use two routers. However you need lots of knowledge and it’s extremely difficult to setup. You might need to buy another expensive router because not all of them supported.
VPN will solve everything still remember it’s not a direct connection you’ll get disconnections. And vpns are not free you have to pay lots of money. Still not recommended only temporary solution or the last option.
LAST OPTION CHANGE THE ISP PROVIDER OR TELL THEM YOU’LL LEAVE YOUR ISP IF THEY NOT FIX IT.
This is how CG-NAT WORKS PICTURE BELOW.