[SunRescue] Networking details (was Re: OT: Advice on Certification)

[David Cantrell]

Magnus Hultin <e5hultin at cd.chalmers.se> wrote:

> When I studied this about two years ago, my teachers told
> the story like this:
> 
> A long time ago, when IP numbers were a new thing, you could
> be assigned either a class A block, a class B block or a class
> C block of numbers.
> 
> Class A would be a /8 network block in the range 1.0.0.0 -
> 126.255.255.255, with 10.x.x.x reserved for private use.
> 
> Class B would be a /16 block in the range 128.0.0.0 -
> 191.255.255.255, with 172.16.0.0 - 172.31.255.255 reserved
> for private use.
> 
> Class C would be a /24 block in the range 192.0.0.0 -
> 255.255.255.255 with 192.168.0.0 - 192.168.255.255
> reserved.

That's pretty close, but even so, you were taught wrong, as that would
mean no multicast.  Class is determined by the first few bits of the
address.

First bit 0 .......... class A
First 2 bits 10 ...... class B
First 3 bits 110 ..... class C
First 4 bits 1110 .... class D (multicast)
First 5 bits 11110 ... "class E" (reserved for future use)

Ignore RFC 1375 - it never happened :-)

-- 
David Cantrell | root at alphacomplex.org | http://www.cantrell.org.uk/david/

  Rip, Mix, Burn, unless you're using our "most advanced operating system
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