Subnetting moment of duh
pwjohnston
Member Posts: 441
in CCNA & CCENT
I’ve obviously missed this somewhere. Can you guys direct me to a chapter to read in the Odom book or something online?
If you give me an IP and a Subnet Mask (dot decimal or slash) I can derive decimal subnet, ip range, broadcast, no problem. RP-6C is practically ingrained in me by now I hope. I can convert binary to base 10. I can usually derive the Network bits, subnet bits, and host bits from a subnet mask and tell you how many subnets and hosts can be created.
But I keep running into a question where is says something like;
Given a subnet mask (insert any mask) which of the following addresses can be assigned to network hosts?
Then I’m given a list of (valid IPv4) hosts IPs and no network IP.
Where am I going wrong here?
If you give me an IP and a Subnet Mask (dot decimal or slash) I can derive decimal subnet, ip range, broadcast, no problem. RP-6C is practically ingrained in me by now I hope. I can convert binary to base 10. I can usually derive the Network bits, subnet bits, and host bits from a subnet mask and tell you how many subnets and hosts can be created.
But I keep running into a question where is says something like;
Given a subnet mask (insert any mask) which of the following addresses can be assigned to network hosts?
Then I’m given a list of (valid IPv4) hosts IPs and no network IP.
Where am I going wrong here?
Comments
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binargs
Member Posts: 55 ■■□□□□□□□□
most of those times the question asks to to know which of the given address can not be a host, so the list of addresses can be either network numbers or bcast numbers. use the subnet knowledge to find out which ones are invalidl. -
blackninja
Member Posts: 385
pwjohnston wrote: »Given a subnet mask (insert any mask) which of the following addresses can be assigned to network hosts?
Then I’m given a list of (valid IPv4) hosts IPs and no network IP.
Where am I going wrong here?
E.G.
192.168.0.0 255.255.255.0 (/24)
a) 192.168.0.10 - 192.168.0.100
b) 192.168.1.1 - 192.168.1.254
c) 192.168.0.1 - 192.168.0.254
d) 192.168.0.0 - 192.168.0.255
The answer is cCurrently studying:
CCIE R&S - using INE workbooks & videos
Currently reading:
Everything. Twice
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1number9
Member Posts: 13 ■□□□□□□□□□
Since you are able find the range of a network based on the mask then all you have to do is find the address that falls in between the network and broadcast.
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miller811
Member Posts: 897
pwjohnston wrote: »I’ve obviously missed this somewhere. Can you guys direct me to a chapter to read in the Odom book or something online?
Where am I going wrong here?
have you read this post yet?
This is what made it click for me
http://www.techexams.net/forums/ccna-ccent/38772-subnetting-made-easy.html
this should really be a stickyI don't claim to be an expert, but I sure would like to become one someday.
Quest for 11K pages read in 2011
Page Count total to date - 1283 -
pwjohnston
Member Posts: 441
pwjohnston wrote: »Then I’m given a list of (valid IPv4) hosts IPs and no network IP.
Should I bother reiterating this portion? -
mikej412
Member Posts: 10,086 ■■■■■■■■■■
It's in the post of links I did in the CCNA FAQ thread -- and will probably be link #1 if we add a subnetting section in the next FAQ update.this should really be a sticky:mike: Cisco Certifications -- Collect the Entire Set!
