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hellokittycatty
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Help me with subnetting! Need specs for net A and net B

Fri Jun 15, 2012 2:57 am

Hi, I just want to get this course over with and this is the last assignment. The only reason I took this course is because one networking class was required to for Computer Information and Programming. I know this is basic stuff but i have gone sort of blank. I've put question marks after the answers because I'm not certain of it and I would gladly be corrected if I'm wrong.

IP address and mask: http://i.imgur.com/mCWBP.jpg


Subnet A
Specification
hosts: http://i.imgur.com/wbhZU.jpg

Number of bits in the subnet : 25?
IP mask (binary) : 11111111.11111111.11111111.10000000?
New IP mask (decimal) : 255.255.255.128?
Maximum number of usable
subnets (including the 0th subnet) : 2?
Number of usable hosts per subnet: 126?
IP Subnet : ??
First IP Host address : 192.168.10.1?
Last IP Host address : 192.168.10.126?



Subnet B
Specification
hosts: http://i.imgur.com/dWHk0.jpg

Number of bits in the subnet : 26?
IP mask (binary) : 11111111.11111111.11111111.11000000?
New IP mask (decimal) : 255.255.255.192?
Maximum number of usable
subnets (including the 0th subnet) : 4?
Number of usable hosts per subnet: 62?
IP Subnet : ??
First IP Host address : 192.168.10.129?
Last IP Host address : 192.168.10.190?



-----------------------------------------------------------
Device -||- IP address -||- Mask -||- Gateway
======================================
Host1 -||- ??? -||- ??? -||- ???
Router1-Fa0/0 -||- ??? -||- ??? -||------------
Host2 -||- ??? -||- ??? -||- ???
Router1-Fa0/1 -||- ??? -||- ??? -||------------

Okay, that's how far I've come. Thanks in advance!

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matgar
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Re: Help me with subnetting! Need specs for net A and net B

Fri Jun 15, 2012 3:38 am

Your mostly correct.
One thing is that you have mixed up the way you answer with the number of bits in the subnet mask = 25 in A and then on B you specify the number of subnet bits 2.
use the same way to state it. Either its 25 and 26 or of its just the bits used for subnetting its 1 and 2.


As for the IP subnet its simply that first ip in a range which you cant use on a host.

For your last questions about hosts and routers. Im not sure what the task is. But for hosts any usable ip in the "subnet".
Routers normally get the first (or last) usable ip in the (sub)net. And of course then gets used as gateway for the hosts.

hellokittycatty
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Re: Help me with subnetting! Need specs for net A and net B

Fri Jun 15, 2012 3:57 am

matgar wrote:Your mostly correct.
One thing is that you have mixed up the way you answer with the number of bits in the subnet mask = 25 in A and then on B you specify the number of subnet bits 2.
use the same way to state it. Either its 25 and 26 or of its just the bits used for subnetting its 1 and 2.


As for the IP subnet its simply that first ip in a range which you cant use on a host.

For your last questions about hosts and routers. Im not sure what the task is. But for hosts any usable ip in the "subnet".
Routers normally get the first (or last) usable ip in the (sub)net. And of course then gets used as gateway for the hosts.

Yeah, that was a typo and I've now edited it.
About the Subnet IP is it supposed to be A: 192.168.10.128 and B: 192.168.10.64 or am I completely wrong?

Edit: And before the last task it says "Host computers will use the first IP address in the subnet. The network router will use the LAST network host address. Write down the IP address information for each device:"
So is it?:

-----------------------------------------------------------
Device -----------||- IP address ------||- Mask ---------------||- Gateway
======================================
Host1--------------||- 192.168.10.1 ----||- 255.255.255.128 -||- 192.168.10.126
Router1-Fa0/0 -||- 192.168.10.126 -||- 255.255.255.128 -||------------
Host2 -------------||- 192.168.10.2 ----||- 255.255.255.128 -||- 192.168.10.126
Router1-Fa0/1 -||- 192.168.10.126 -||- 255.255.255.128 -||------------

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matgar
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Re: Help me with subnetting! Need specs for net A and net B

Fri Jun 15, 2012 4:29 am

hellokittycatty wrote:About the Subnet IP is it supposed to be A: 192.168.10.128 and B: 192.168.10.64 or am I completely wrong?

Those are valid IP Subnets.
For a /25 192.168.10.0/25 and 192.168.10.128/25 are valid.

For a /26 .0 .64 .128 and .192 are valid.

hellokittycatty wrote:Edit: And before the last task it says "Host computers will use the first IP address in the subnet. The network router will use the LAST network host address. Write down the IP address information for each device:"


So is it?:

-----------------------------------------------------------
Device -----------||- IP address ------||- Mask ---------------||- Gateway
======================================
Host1--------------||- 192.168.10.1 ----||- 255.255.255.128 -||- 192.168.10.126
Router1-Fa0/0 -||- 192.168.10.126 -||- 255.255.255.128 -||------------

This part looks good to be.
But for host2 and the Fa0/1 is this supposed to be from Subnet B? Then it cannot conflict with the 192.168.10.0/25 network.
So you go for a /26 after the first /25 subnet.. so either 192.168.10.128/26 or 192.168.10.192/26

hellokittycatty
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Re: Help me with subnetting! Need specs for net A and net B

Fri Jun 15, 2012 4:36 am

Thanks a lot for the help matgar!

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