Just to summarize: The direction I'll be looking in is at the firewalls which were presumably installed automatically on my Debian computers (Wheezy, Jessie, and Trixie), to see if they are blocking 192.168.12.x, and, if so, "open" them up.
On Friday, February 13, 2026 03:33:47 AM john doe wrote: > On 2/12/26 22:42, [email protected] wrote: > Why, were you having IP conflict/why did you have to change the IPv4 > addressing of your network? Because the TMO device, my interface to the Internet, uses address 192.168.12.1 and cannot be changed. (Confirmed by its manual and various references on the Internet.) > How did you determine, the service(s) that are running on your ISP > "router"? From its manual and various references on the Internet. > YOu are using static addressing, so you should be able to talk to one > another. Yes, I remember / understand that now. > Just try with double natting for now and see how it goes.. I might do that. I've had a fair amount of trouble just getting VoIP working again after (1) Google voice stopped supporting Obi devices, and (2) I fat- fingered something and lost the GV configuration in my Obi200. The Obi200 could have continued to work with that configuration indefinitely until Google made some incompatible change. (But eventually that would have happened, so the pain of making the related changes was going to happen sooner or later.) > An option but why.. Well, since Dan Purgett clarified my thinking about the need for a router to talk between computers on my LAN (it is not needed), I'll no longer consider the three options, I'll look to learn enough about the firewalls to see if they are blocking 192.168.12.x > If you can not have your own cable modem or set that ISP thing in bridge > mode, look if you have a DMZ capability and add the Edge Router in that > DMZ. I cannot have my own modem, as it is a 5G modem / interface built into what T- Mobile calls their TM0-G4AR gateway. Their literature and other soureces on the Internet say it cannot be set into bridge mode. > Also test your set up as simple as possible than add more switches.. > Are your switches layer 2/3, are they able to provide routing capability? They are (to me) very simple consumer grade 5 and 8 port switches. No idea of the layer.
