Hi all,
On the same track then can someone confirm whether I'm right about the
following list of reserved addresses within Class A,B and C:
10.0.0.0 255.0.0.0
127.0.0.0 255.0.0.0
172.16.0.0 255.240.0.0
192.168.0.0 255.255.0.0
I've always believed these to be correct, but are they and are there any
others?
Thanks,
Gareth
"Ole Drews Jensen" <[EMAIL PROTECTED]> wrote in message
2019FB428FD3D311893700508B71EBFB4849A8@RWR_MAIL_SVR">news:2019FB428FD3D311893700508B71EBFB4849A8@RWR_MAIL_SVR...
> We're probably of the same opinion, but talking two different languages.
>
> Would it be correct to say that:
>
> CLASS A networks MSB in the first octet is 0, hence it has the following
> range:
>
> 0.h.h.h - 127.h.h.h
>
> After that has been said, we would go a step further and look at network
> addresses in Class A that can be used.
>
> We all know that 127.h.h.h is reserved for loopback, and the network
address
> cannot be all 0's, hence the addresses we're looking for has the following
> range:
>
> 1.h.h.h - 126.h.h.h
>
> If this is true, I must assume that the following goes with Classes B and
C:
>
> Class B range:
>
> 128.0.h.h - 191.255.h.h
>
> Class B usable addresses:
>
> 128.1.h.h - 191.254.h.h
>
> Class C range:
>
> 192.0.0.h - 223.255.255.h
>
> Class C range:
>
> 192.0.1.h - 223.255.254.h
>
> Am I correct in those statements? - If not, please explain.
>
> Thanks,
>
> Ole
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Ole Drews Jensen
> Systems Network Manager
> CCNA, MCSE, MCP+I
> RWR Enterprises, Inc.
> [EMAIL PROTECTED]
> http://www.oledrews.com/ccnp
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> NEED A JOB ???
> http://www.oledrews.com/job
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
> -----Original Message-----
> From: Leigh Anne Chisholm [mailto:[EMAIL PROTECTED]]
> Sent: Monday, December 18, 2000 1:18 PM
> To: Ole Drews Jensen; Cisco@Groupstudy. Com
> Subject: RE: IP addressses - Are networks 2^x or (2^x)-2 ???
>
>
> I disagree. You've identified the VALID range of Class A, B, and C
> addresses - addresses that can be assigned to end-systems. You have NOT
> identified the FULL SCOPE of the Classes.
>
> As per your previous email:
>
> On RFC 943 (Assigned Numbers) it says on page 1:
>
> Class A has 7 bit network number which allows 128 (2^7) networks.
> Class B has 14 bit network number which allows 16384 (2^14) networks
> Class C has 21 bit network number which allows 2097152 (2^21) networks
>
> Class A addresses are those where the first octet value begins with 0.
> Thus, all addresses in the range of 0.0.0.0 through 127.255.255.255 are
> Class A addresses. Using the formula 2^n-2, you identify those addresses
> within that range that can be used on end-systems. Using the formula
2^n-2,
> you create the valid IP address range from within the Class A address
range
> of 1.0.0.0 through 126.255.255.255...
>
> Class B addresses are those where the first octet value begins with the
> combination "10". Class B addresses are in the range of 128.0.0.0 through
> 191.255.255.255. The VALID range of Class B IP addresses is determined by
> the formula 2^n-2 when applying the Class B default subnet mask of
> 255.255.0.0.
>
> Class C addresses are those where the first octet value begins with the
> combination "110". Class C addresses are in the range of 192.0.0.0
through
> 223.255.255.255. The VALID range of Class C IP addresses is determined by
> the formula 2^n-2 when applying the Class C default subnet mask of
> 255.255.255.0.
>
> What John was pointing out, is that once you apply IP subnet zero, what
> you've posted below as the VALID END-SYSTEM ASSIGNABLE range of IP
addresses
> changes (but the FULL SCOPE of the classes always remains the same).
>
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> Ole Drews Jensen
> Sent: December 18, 2000 9:59 AM
> To: Ole Drews Jensen; '[EMAIL PROTECTED]'
> Subject: RE: IP addressses - Are networks 2^x or (2^x)-2 ???
>
>
> Let me reconstruct my message.
>
> After having read through some more RFC's, I now believe that the
following
> is the truth. If you do not agree, please reply.
>
> CLASS A : 1.h.h.h - 126.h.h.h = 126 networks
> CLASS B : 128.1.h.h - 191.254.h.h = 16382 networks
> CLASS C : 192.0.1.h - 223.255.254.h = 2097150 networks
>
> and
>
> CLASS A : n.0.0.1 - n.255.255.254 = 16777214 hosts
> CLASS B : n.n.0.1 - n.n.255.254 = 65534 hosts
> CLASS C : n.n.n.1 - n.n.n.254 = 254 hosts
>
> Thanks,
>
> Ole
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Ole Drews Jensen
> Systems Network Manager
> CCNA, MCSE, MCP+I
> RWR Enterprises, Inc.
> [EMAIL PROTECTED]
> http://www.oledrews.com/ccnp
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> NEED A JOB ???
> http://www.oledrews.com/job
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
> -----Original Message-----
> From: Ole Drews Jensen [mailto:[EMAIL PROTECTED]]
> Sent: Monday, December 18, 2000 8:21 AM
> To: '[EMAIL PROTECTED]'
> Subject: IP addressses - Are networks 2^x or (2^x)-2 ???
>
>
> I thought I knew it by heard now, but when I had to prove a point to
> someone, I grapped some of my books, and they all have different
> explanations. I therefore jumped to IETF's homepage and started surfing
> their RFC's. BUT...
>
> On RFC 943 (Assigned Numbers) it says on page 1:
>
> Class A has 7 bit network number which allows 128 (2^7) networks.
> Class B has 14 bit network number which allows 16384 (2^14) networks
> Class C has 21 bit network number which allows 2097152 (2^21) networks
>
> This looks right, because the MSB is 0 in a Class A, thus the 7 bits. It
is
> only 127 networks though, since 127.x.x.x is reserved. That is also
> explained later in the RFC. The MSB in Class B is 10, thus the 14 bits.
And
> finally, the MSB in Class C is 110, thus the 21 bits.
>
> On page page 10 however, it says that the maximum allowed networks are:
>
> Class A : (2^7 - 2) 126
> Class B : (2^14 - 2) 16382
> Class C : (2^21 - 2) 2097150
>
> It now looks like it follows the same rule as host calculations, where you
> cannot use all 0's or all 1's.
>
> I have looked through all my books (I have a lot) and they all have
slightly
> different opinions about this.
>
> What is the right answer?
>
> Class A is from 0.x.x.x to 126.x.x.x OR 1.x.x.x to 126.x.x.x ?
>
> Class B is from 128.0.x.x to 191.255.x.x OR 128.1.x.x to 191.254.x.x ?
>
> Class C is from 192.0.0.x to 223.255.255.x OR 192.0.1.x to 223.255.254.x ?
>
> Regarding SUBNET's, they all have the same explanation, but here it is
> anyway. If you use 192.168.1.0/28, you have 4 bits for the subnet and 4
bits
> for the hosts, which give you 2^4 - 2 = 14 subnets with 14 hosts each. I
am
> pretty sure that that is the right explanation.
>
> Thanks for any comments on this,
>
> Ole
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Ole Drews Jensen
> Systems Network Manager
> CCNA, MCSE, MCP+I
> RWR Enterprises, Inc.
> [EMAIL PROTECTED]
> http://www.oledrews.com/ccnp
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> NEED A JOB ???
> http://www.oledrews.com/job
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
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