On Fri, Feb 3, 2017 at 12:08 PM, John R Pierce <pierce at hogranch.com> wrote: > for Comcast/Xfinity, I'm using a Arris SB6183 that I got at Costco. this > is a simple modem/bridge, so /my/ router behind it gets the public IP. Note that some residential ISPs may not offer "naked" Internet, and/or won't allow you to bring your own device (BYOD). At least in my area, there are only two options for residential Internet; cable-based via Comcast, and DSL-based via AT&T. I used to routinely switch back and forth between the two, to play them against each other for the best rates. However, I had to give up on AT&T because they stopped offering a "naked" service. That is, when I was using them, I had the most basic DSL modem, that literally did nothing except provide me with a public Internet IP and the service. Last I talked to them, I could only use their service with their fancy all-in-one devices, that are both a DSL modem and gateway/router/wireless AP. I already have all that infrastructure in my house, and I trust my ability to manage it more than I trust the blackbox firmware that AT&T provides. Going from memory, that all-in-one DSL service did give me a public IP, but the device itself implemented NATing, so it looked like I was getting a private IP. There *may* have been a way to remove most of the functionality of the all-in-one device ("DMZ mode" or something like that); it's been discussed pretty heavily on the DSLReports Forums. (But, either way, even ignoring the technical grievances with their service, AT&T's prices are higher and speed tiers lower than Comcast's.) TL;DR: (1) some ISPs may not allow BYOD; (2) if it looks like your ISP is giving you a private IP, dig a little deeper, it could simply appear that way due to the way the ISP configures the assigned device.