Hot Downloads



The forum is in read only mode.
Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1

TOPIC: Error in the tutorials...

Error in the tutorials... 11 years 10 months ago #27547

  • NeoTech
  • NeoTech's Avatar Topic Author
  • Offline
  • Distinguished Member
  • Distinguished Member
  • Posts: 101
  • Thank you received: 0
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 to shouldnt this be (with range to 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:


Re: Error in the tutorials... 11 years 10 months ago #27551

  • SteveP
  • SteveP's Avatar
  • Offline
  • Distinguished Member
  • Distinguished Member
  • Posts: 161
  • Thank you received: 0
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!

Re: Error in the tutorials... 11 years 10 months ago #27611

  • Smurf
  • Smurf's Avatar
  • Offline
  • Moderator
  • Moderator
  • Posts: 1390
  • Karma: 1
  • Thank you received: 0
Steve, thats how i understand it also.
Wayne Murphy Team Member

Now working for a Security Company called Sec-1 Ltd in the UK, for any
Penetration Testing work visit or PM me for details.

Re: Error in the tutorials... 11 years 1 month ago #30611

Hey that was a nice tutorial. I think adding the below would further clarify some facts....
  • Page:
  • 1
Time to create page: 0.114 seconds


Cisco Routers

  • SSL WebVPN
  • Securing Routers
  • Policy Based Routing
  • Router on-a-Stick

VPN Security

  • Understand DMVPN
  • GRE/IPSec Configuration
  • Site-to-Site IPSec VPN
  • IPSec Modes

Cisco Help

  • VPN Client Windows 8
  • VPN Client Windows 7
  • CCP Display Problem
  • Cisco Support App.

Windows 2012

  • New Features
  • Licensing
  • Hyper-V / VDI
  • Install Hyper-V


  • File Permissions
  • Webmin
  • Groups - Users
  • Samba Setup