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TOPIC: Error in the tutorials...

Error in the tutorials... 8 years 2 months ago #27547

  • NeoTech
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Hey guys, just wanted to point out an error in the subnetting tutorials...
Its a minor thing but could confuse some people.
In the 'subnetmasks and their effect' page, where it lists the classed ip ranges, it states that class A is 1.0.0.0 to 127.255.255.255. shouldnt this be 126.255.255.255? (with range 127.0.0.0 to 127.255.255.255 being reserved for loopbacks and all).
Or is it actually still considered a class A? Is it down to the binary placement in the Subnet mask? (128 being another network).

OMG :shock: I've never looked at it that way before. That makes all the other classes beginning and end addresses make sense! lol!

Cheers! :wink:

Neo
Tech
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Re: Error in the tutorials... 8 years 2 months ago #27551

  • SteveP
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As far as I'm aware, 127.x.y.z is, technically, a class A address.

The way I look at it is when you examine the first octet:

if it starts 01xxxxxx, it's class A
if it starts 10xxxxxx, it's class B
if it starts 110xxxxx, it's class C
if it starts 1110xxxx, it's class D
if it starts 11110xxx, it's class E

I'm fairly sure that 0.x.y.z can't be used and, as you say, 127.x.y.z are all loopback.

I hope that I'm not talking out of my rear end!
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Re: Error in the tutorials... 8 years 1 month ago #27611

  • Smurf
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Steve, thats how i understand it also.
Wayne Murphy
Firewall.cx Team Member
www.firewall.cx

Now working for a Security Company called Sec-1 Ltd in the UK, for any
Penetration Testing work visit www.sec-1.com or PM me for details.
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Re: Error in the tutorials... 7 years 5 months ago #30611

  • gvkalra
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Hey that was a nice tutorial. I think adding the below would further clarify some facts....

http://itknowledgeexchange.techtarget.com/cisco/determining-the-network-id-using-the-logical-and-operation/
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