Netgear CM400

> [...] I cannot connect to my security cameras from my desktop or
> phone. [...]

   Not a very detailed description of any of these devices, or how
they're employed.

   "cannot" is not a useful problem description.  It does not say what
you did.  It does not say what happened when you did it.  As usual,
showing actual actions with their actual results (error messages, LED
indicators, ...) can be more helpful than vague descriptions or
interpretations.

   How, exactly, are you trying to "connect" to your (unspecified) "my
security cameras"?  Some app?  Web browser?  (Actual URL?)  Are you
using your public IP address?  Do you know what that is?

> [...] The old server address was 68.7.66.65, what would be the server
> address for this unit? [...]

   That depends on your ISP (Cox).  A CMxxx is a simple cable-TV modem,
not a modem+router.  Your (unspecified) _router_ is the device which
should get your public IP address, and that doesn't depend directly on
your modem.  Talk to your router to determine its WAN/Internet address.
Or, visit one of the many "What is my IP address?" web sites out there.

> [...] 192.168.100.1 does not work.

   Regarding "does not work", see "cannot", above.  What kind of "does
not work"?  "192.168.100.1" should get you to your cable-TV modem, but
it does not have the answer; your router should.

   If your public IP address is subject to change, then you might want
to explore "Dynamic DNS" ("DNS") services which your (unspecified)
router may support.  That would allow you to use a (fixed) DNS name
instead of a (variable) IP address.  The DDNS system should keep the

name pointed to your (wandering) public IP address.