Original Xbox DMZ Host Connection to Xbox 360

did u try and place your xbox ip in the dmz host. dmz host basicly allows you to put a deivice outside of the routers filtering.

It did it again, so i checked my DSL settings, I have Verizon so the DMZ Hosting opens up the NAT and what was originally set by me to be used by the xbox had gotten changed by my directv dvr box. along with a few other settings on my modem. for some reason
the directv dvr changes the setting whenever it wants to use the internet connection to record or update or whatever which i think is really dumb so i held the little master reset on the back of the modem for about 30 seconds and redid dmz hosting for the
xbox now it works again. stupid directv.....

it seems like you've tried almost everything, my suggestion would be to set your xbox as a dmz host, meaning it will be outside of your firewall.

assign your xbox a static ip address

Select Firewall Settings on the top.

Select DMZ Host on the submenu.

Check the box for DMZ Host IP Address.

Enter the IP address of the Xbox.

Select Apply.

Select OK

routerguide.net/when-and-how-to-setup-dmz-host-for-home-use

www.xb1.co.uk/.../how-to-set-up-a-dmz-for-your-xbox-one-router

OK, I changed the DMZ Host to match my Xbox and changed the MTU to 1400, but still getting ICMP error or it's connecting and Xbox Live is still not making all the content available to me.