Question Private/public IP addresses

[jekyllz]

This is a question I cannot solve myself, despite having the answer.

Question: Which one of the following can’t be a public Internet IP address?

a) 217.9.215.1
b) 197.165.276.1
c) 162.198.207.3
d) 174.158.254.203

Answer: b) 197.165.276.1

IANA private ranges are:
10.0.0.0 to 10.255.255.255
172.16.0.0 to 172.31.255.255
192.168.0.0 to 192.168.255.255

So why 197.165.276.1 can’t be a public IP address? Are there any extra private ranges not included in the IANA list ?

 

[AllanGH]

276

 

[bill001g]

Be aware there is another block used for carrier nat that is not public many of the question you find on tests are so old they do not take that into account but they really should.

In this case as mentioned above the ip address is not public because it is private it is not public because it is invalid. Someone trying to be tricky.

 

[jekyllz]

Ohhhh, now I understand. 276 is above 255. Thanks.

 

[failboat]

You have to look at ip addr by bits to get this. 0-255 is the range. each one is 8-bits, which has 256 possible combinations.