Problem with my WAN IP address

[Bardovci]

So I was going to make a server to play with my friends. I recently got a new ISP with DOCSIS 3 and they got me a modem/router with it. I go through the basics port forwarding the ports. Then i give my external IP to my friends and they can't connect.

Then I notice on my router it has a different WAN IP (I'm not using a proxy) then when i check online. So I give my friends the IP from my router and only friends that have the same ISP as me can connect.

I have a technicolor tc7200 modem/router.

 

[boosted1g]

You need to get a dynamic DNS service and configure your router/computer to sync your IP address with that.
Then give your friends that dynamic DNS addres instead