Tom Emerson wrote:
>
> Mike asked:
>
> Okay...I'm convinced that I do need a specific IP address on my HP3000. I
> know that when my ASE was here back in November he used NMMGR to put in a
> random IP address. Something like 192.0.0.0 or some such number. I guess
> what I really need to know is does this number need to be a FCC licensed
> IP address or can it be just a random number? I'm showing my ignorance
> here on IP addressing.
> --
> Mike Farrell
> Intermountain Gas Company
> Data Center Operations Supervisor
> 555 South Cole Road
> Boise, ID 83707
> =========================================================================>
> The [brief] answer:
> IF you are not planning on connecting the HP to "the internet"
> THEN use any random number, preferrably starting with 192.x.x.x (avoid
> x.x.x.0, x.x.x.1, x.x.x.127, & x.x.x.255)
> ELSE
> contact the NIC (Network Information Center) for a proper
> domain/organization name and number.
> ENDIF
>
> The [Longer] answer:
> IP addresses are broken into 4 major categories, named class A, class B,
> class C, and class D (actually, there is a class E and [I think] a class F
> as well, but these are VERY rare -- you'll see why when I explain how these
> work). Think of IP addresses as a full 32 bit number broken down into two
> components -- the network number and the computer number. The "class"
> defines how many bits are used to determine the network number, the
> remaining bits are used to indicate which computer within that network you
> are addressing. To simplify matters, IP addresses are typically broken down
> into four 8-bit quantities. The class is derived by the number of bits used
> at the head of the number (MSB's) and works out something like this:
>
> CLASS A: FIRST 8 bits
> CLASS B: first 16 bits
> CLASS C: first 24 bits
> CLASS D: first 28 bits [warning: shakey memory being accessed here...]
>
> This means that there can ONLY be (theoretically) 256 class "A" licenses IN
> THE WORLD, however, each "class A" license can encompass 2^24 computers.
> Likewise, there are 16386 class "B" licenses, each capable of addressing
> 16386 computers, and finally, (or, "most commonly"), class C licenses, of
> which 2^24 can exist, but each can only addresss 256 computers. Note that
> these are "theoretical" maximums. Since there needs to be some way to
> differentiate the classes, there is a further breakdown within these bit
> groupings.
>
> For instance, given the above, would the address 1.2.3.4 be:
> computer 2.3.4 in class A network 1?
> computer 3.4 in class B network 1.2?
> computer 4 in class C network 1.2.3?
>
> To resolve this ambiguity, the first byte of the address is broken down even
> further to indicate which class the rest of the number is to be interpreted
> as. This breaks down to:
> CLASS A is assigned a range of 0 - 127
> CLASS B is assigned a range of 128 - 191
> CLASS C is assinged a range of 192 - 223
> CLASS D is assigned a range of 224 - 239
>
> Or, if you look at the bit patterns, these are:
> 00000000 - 01111111 (class A)
> 10000000 - 10111111 (class B)
> 11000000 - 11011111 (class C)
> 11100000 - 11101111 (class D)
> and so on.
>
> This effectively limits class A licenses to 128, class B to 64 * 256, and
> class C to 32 * 16386. Classes D, E, and F are used so rarely because while
> there may be a great number of them, they can only access a few machines
> within the network (in other words, if the first 28 bits of a 32 bit number
> are being used for the network number, there can only be 16 machines on the
> network, but as "machines" with numbers of all zeroes and all 1's are
> pre-defined for other purposes, there can only be 14 local addresses...)
>
> However, as I mentioned above, if you don't intend to connect this "network"
> to "the internet", you can pick any scheme you want (although using class
> "C" is recommended). If you DO intend to connect to "the internet"
> (eventually), then you must contact not the FCC (although that's a good
> guess), but Internic, or Internet Network Information Center (usually just
> referred to as "NIC") as they are "in charge" of administering class
> licenses and network numbers. This used to be a "free" service, but lately
> I believe they have begun to charge $50 or $100 per year to maintain the
> license (this is simply a supply/demand problem -- as I pointed out above,
> the supply is certainly limited, but the "demand" is quickly approaching the
> total number of computer users in the world as each and every user seems to
> want "their own" internet address...)
>
> There are plenty of books on TCP/IP that explain all the above in even
> greater detail (including how to contact the NIC) which is where I'll direct
> you to for further enlightenment.
>
> Tom EmersonTom,
You are a gentleman and a scholar. Your explanation was "everything I
wanted to know but was afraid to ask." Thanks so much for the bonus
information.
--
Mike Farrell
Intermountain Gas Company
Data Center Operations Supervisor
555 South Cole Road
Boise, ID 83707
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