a page flaw i seen

I've actually edited this reply because there seems to be a confusion about the 127.x.x.x IP address as to whether it is a Class A address or not.

The diagram provided in the IP Classes page clearly states that the "above IP Addresses are not all usable by hosts" which means that there are certain IP Addresses we cannot assign to hosts.

The 127.x.x.x.x IP address is also one of these "unusable" addresses (as noted at the bottom of the same page, in the table I created).

So is 127.x.x.x a Class A IP Address or not?

The answer is "yes" - It's considered an Class A IP Address.

The theory for all Class A ip addresses states all such addresses with have their first octet starting with a Zero: 0xxx xxx.xxxx xxxx.xxxx xxxx .

As such, any IP address in the above format, is considered a Class A address. Since 127.255.255.255 translates to 0111 1111. 1111 1111.1111 1111 in binary, it clearly falls within the Class A specifications.

So, we conclude that its a valid Class A address, but is not usable since its used only as a loopback IP Address for the local machine that has the TCP/IP protocol configured.

If anyone would like to comment on the above, please feel free to do so.

Cheers,

Cheers,

When a man thinks in binary, you cannot fault him....

:lol:

I agree that 127.0.0.1 is still a class A address, it is just reserved, similar to 192.168.0.1 falls within the Class C addresses, but it is reserved as a Private address.

I have seen class A as up to 126 or 127, depending on who is defining it. Strictly speaking it is a Class A address, as Chris says.

It might be good to modify the page to mention what the special addresses are, but I also understand that Chris is trying to keep this as simple as possible. He also doesn't mention the Broadcast addresses (host id with all bits on) or the network address (host id with all bits off) or the private addresses (as I mentioned) or Class D and Class E.

This would be confusing to someone just learning, and this is supposed to be the basics.