The ports needed by the Xbox Live are:
-Port 88 (UDP)
-Port 3074 (UDP and TCP)
-Port 53 (UDP and TCP)
-Port 80 (TCP)
In order to open these ports, please use the IP address of your router in the browser. It should be something like 192.168.2.1 / 192.168.0.1 / 192.168.1.1. These are the common ones, but if you don't find it, just open a Command Prompt and type ipconfig /all. The IP assigned as Gateway is the IP of your router. If you need to log in, use admin/admin as username and password or simply admin as username. Go to NAT or Advanced > Port forwarding and enter each port using its configuration settings.
To get the IP of your XBOX, turn on the device, go to Settings > Network. Type the IP down on a paper then go to the configuration page on router.
For example if the Xbox IP is 192.168.1.2 then the port forwarding rule should look this way for 80 port.
XBOX / 80 - 80 / 192.168.1.2 / TCP
name / port range / IP / protocol