What does the IP "192.168.1.1/24" indicate? [duplicate]
Indeed, that means the first 24 bits of the 192.168.1.1 address are required while the remaining eight can be anything. This is called CIDR.
Yes. The notation is CIDR - have a look here for some more discussion.
Yes it means 127.0.0.1 and 192.168.1.* are allowed.