IP-address (v4) is consisted of 32 bits. Any self-respecting administrator or IT specialist should answer correctly the question: "How many bits are in an IP-address?" Of course, It is desirable to know about IPv6: 128 bits.
Here is a first case. Theoretically IPv4-addresses can be:
232 =210*210*210*22 = 1024*1024*1024*4 ≈ 1000*1000*1000*4 = 4 billion
Below we could see that a lot of them are "eaten up" by any garbage.

I think everyone knows how IPv4-address is written. The four octets (it is the same as byte) in decimal with no leading zeros, separated by dots: “”.
ZimerMan 19 march 2012, 13:20