The Arris 822g is a solid 8x4 docsis 3 modem. I agree tho, some of their previous offerings were really meh.. especially anything with a built in router / wireless..
Ok so here's my progress.
I disabled streamboost, this broke the ability to RDP behind the 5500.
I remote admined in and set the VPN box as DMZ, this broke the ability to remote admin via 8080, VPN still broken.
I'm at work and locked out of the device. I am going to reset it when I get home.. and recofigure just the basics then add things one by one and test. I don't wan't to believe the initial firmware is this buggy.. ugh.
Ok, I've asked for some additional review and information on this. Please be patient. I hope we get some information.
Arris isn't the best modem IMO, however if it's been working. No problem there.
Keep us posted.