UniFi USG with CM1000

> [...] VPN [...]
> I bought a UniFi USG 3P [...]

   I know approximately nothing about either topic, but...

> The CM1000 does not have a bridge mode and LPTT. [...]

   I know nothing about LPTT, but I'd say that the CM1000 does not have
a _router_ mode.  It's a cable-TV modem, not a cable-TV modem+router.
I'd say that a _bridge_ mode is about all that it _does_ have.

> [...] The CM1000 is setup with a hardware address of 192.168.100.1 on
> the WAN port. [...]

   I wouldn't say that.  Its web server responds at that address, but
that's a DOCSIS thing which is generally independent of your
communication with your ISP.

> [...] So I set the WAN port of the USG to 192.168.1.2

   Why?  Whence came that address?  Did you mean "192.168.100.2"?  I
would not expect that to improve anything.  My suggestion would be to
forget all about the 192.168.100.0/24 subnet (except when you want to
talk to the CM1000 itself).

   I'd expect the gizmo which is connected to the CM1000 to talk to your
ISP, and (most likely) get its WAN configuration from that ISP.  If you
connect a computer directly to the CM1000, how does it get configured?
My guess would be that it gets your public IP address.  I'd expect that
that's what should happen to anything which you connect to the CM1000
(or any other cable-TV modem).

> [...] and I cannot get out to the internet.

   With that configuration, I'm not amazed.


> Sorry... I meant to type IPPT.... IP Pass Through

   Another region of my ignorance.

   At least one of us may need to read and understand the documentation
on your UniFi Security Gateway.