Creating and Maintaining Home Networks
Internet Service Provider (ISP)


Wikipedia: Internet Service Provider (ISP)
  An Internet service provider (ISP) is an organisation that
  provides services for accessing, using, or participating in
  the Internet. Internet service providers can be organized in
  various forms, such as commercial, community-owned,
  non-profit, or otherwise privately owned.

  Internet services typically provided by ISPs can include
  Internet access, Internet transit, domain name registration,
  web hosting, Usenet service, and colocation.

  An ISP typically serves as a connection or gateway that
  provides a user, access to everything available on the

Who is My Current Internet Service Provider?
What is My Current Internet Service Provider Bandwidth/Speed?

Wikipedia: Carrier-grade NAT
  Many cell phone carriers (AT&T, Verizon, T-Mobile, etc.) and
  Some Fiber Optic ISPs use Carrier-grade NAT as there are not
  enough IPv4 addresses for all of their customers.

  From the command line:
  traceroute -aI `curl --connect-timeout 1 -s`
  If more than one hop, your IP address is behind a NAT.

  open -a "AirPort" to demo router's 
    WAN IP address
    LAN IP address

  If your WAN IP address, as shown on your Router, is:     -   (   16,777,216   -   ( 1,048,576  -  (   65,536

  then you are NAT'd. These are private IP addresses, as 
  defined in RFC 1918.
  BeeNetTools (App for iOS, iPadOS) Ping, Traceroute, & MTR