Arlo Base will not connect to internet

I have found that the Xfinity router is not allowing the Arlo base station to connect to the internet.  Arlo needs to have ports 80, 443 and 123 opened for it to connect to the internet.  It appears those ports are blocked on the Xfinity router.  I am told by Xfinity support that port forwarding has to be setup.  However, they do not provide any instructions to do so.  Help!  Anyone else work through this issue?