Question for this IP's PTR

[fh]

Greetings,

as you see this PTR,
$ dig -x 1.1.1.1 +short
one.one.one.one.

so 2.2.2.2 can have the PTR two.two.two.two? and 3.3.3.3 can have 
three.three.three.three?

Sorry I am not good at the DNS knowledge.

Regards.