Is 1.1.1.1 a IP address

Yes, it is an address in one of the private IP address ranges that have been defined and reserved.

The private IP address ranges are set as:

10.0.0.0 through 10.255.255.255

172.16.0.0 through 172.31.255.255

192.168.0.0 through 192.168.255.255

Any address in these ranges can be set up and used by homes, offices, and anyone else and the communication will not be routed to the internet because they are defined as unroutable. They also will not cause any IP address conflicts on the Internet since nothing Internet-accessible exists in those address ranges.

If you have any other questions about IP addressing, feel free to drop me a line.