Hot Downloads



The forum is in read only mode.
Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1
  • 2

TOPIC: undeliverable email

Re: undeliverable email 15 years 8 months ago #2391

  • indebluez
  • indebluez's Avatar Topic Author
  • Offline
  • Distinguished Member
  • Distinguished Member
  • Posts: 114
  • Thank you received: 0
hi guys thanx!
but there has been error for the 1st qn....the mask should have been the subnets masks are 8.0
16.0...multiples of 32

and for the 2nd qn....i jus checked the ans at the celticrover site
under ip addressin
the ans is 124.78.....
hmmm *scratchin head* i still have no clue:(

and for the 3rd the celticrover was asked which
one of the followin networks are used for loopback testing...ands is


Re: undeliverable email 15 years 8 months ago #2392

  • indebluez
  • indebluez's Avatar Topic Author
  • Offline
  • Distinguished Member
  • Distinguished Member
  • Posts: 114
  • Thank you received: 0
hi guys...
oops for the 2nd qn i got it:) the subnet masks are of multiples of 32:)
so the rest are valid hosts:)

but i cant figure out the 3rd qn

Re: undeliverable email 15 years 8 months ago #2393

Hi indebluez,

This is a very simple formula you can always use to calculate subnets:


first subnet address N = 256 - X
second subnet = (N)2
third subnet = (N)3
and so on …


Here X is the octet in which the bits are borrowed for the hosts.

for eg:

Subnet mask:

here 248 is the octet from which bits are borrowed for hosts. In this example 3 bits are borrowed and the total number of hosts possible for this subnet mask per subnet is:

(2 ^ 3) - 2 = 7 Hosts

because 256 - 248 = 8

so for your first question after your correction the subnet addresses will increment in multiples of "8".

for your second question, the answers from the website you are talking about jut cant be correct. You may need to recheck or it’s an error by the author.

the third question ....

IP is like ... your home address ...

if you sent a mail to your home address and if you received it too then you can be sure that the postal service is working fine for your residence address ...

only an analogy ... I’m sure your postal service need not be reinstalled like a defective TCP/IP stack :lol: is reserved as a loopback address or in other words TCP/IP when installed by default assigns itself the IP for loopback testing purpose .... and if you are able to ping this IP then that would mean that your TCP/IP stack is working properly, application thru physical layer and there is no problem with it.

try using this command and figure out who is this "localhost" :wink: :


c:\>ping localhost


hope this helps ...


Re: undeliverable email 15 years 7 months ago #2396

  • indebluez
  • indebluez's Avatar Topic Author
  • Offline
  • Distinguished Member
  • Distinguished Member
  • Posts: 114
  • Thank you received: 0
Hi Syed
i jus checked the answers are the ip addresses with the following numbers for its 1st octet.....its 124....
and 186...but i thawt it was right...coz the mask is 224
and that gives a subnet of 256-224=32
so subnets of 0,32,64,96.....
the ip addresses with these as their 3rd octet shuld be subnets and the rest could be valid hosts right?hmmm
its okye i have plenty of qns today as well...when u configure for PPP....and u type username RouterB passwrd xxx
the username n passwrd should be of the other router right?
and we type this in router A's config? what happens actually?
thx alot indebluez:)

Re: undeliverable email 15 years 7 months ago #2397

  • tfs
  • tfs's Avatar
  • Offline
  • Expert Member
  • Expert Member
  • Posts: 521
  • Thank you received: 0
Also, as to the 3rd question.

The localhost question as been answered pretty well. But the reason you cannot use is because this the network address (the wire). is the normal address for localhost and is listed this way in your hosts file.

But in actuality, any address starting with 127, except (network) and should also work as your loopback address.

If you ping, for instance, you should still get a response. You won't get one for and


subnetting 15 years 6 months ago #2765

  • mew
  • mew's Avatar
  • Offline
  • Frequent Member
  • Frequent Member
  • Posts: 77
  • Thank you received: 0
As to your subnetting question the author is correct for a subnet mask of 32 is what some would refer to as your magic number therefore 32 and 160 are valid subnet address and not host ip addresses.

The last 5 bits of the third octet and all eight bits in the last octet are host bits and you have to have at least one of them as a binary 1. The other three answers meet the criterial of having at least one binary 1 in the last 13 bits.

As to your PPP question the most common mistake is to think of the password as already being used somewhere else i.e. the enable password. This is a totally new password and must be the same on both routers. Otherwise yes to your question as you are making a user list to allow the other router to establish a PPP link with you and the other router has to do the same.

By the way you did not ask about authentication but I am assuming you are configuring this as well and using either PAP or CHAP. Otherwise you do not need a user list.
  • Page:
  • 1
  • 2
Time to create page: 0.109 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