Subnet zero help please?

Just tried a few test questions-here was the subnet zero question

131.64.16.133 mask /25 192.168.36.10 mask /24 156.100.11.37 mask /20 200.100.16.3 /24

Thanks alot

Reply to
gregg johnstone
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Where is the question, don't see it....

The Dude

Reply to
The Dude

I think it's "which is an example of a subnet zero". The answer being "156.100.11.37 mask /20".

BernieM

Reply to
BernieM

Reply to
gregg johnstone

Reply to
gregg johnstone

I'm not sure what you mean. ".11.37" is a host addr. The actual subnet is "156.100.0.0"

Host addr's are 156.100.0.1 through to 156.100.15.254 Broadcast addr is 156.100.15.255 Next subnet is 156.100.16.0

Yes.

Traditional 'classful' networks masks were:

'A-class' (8-bit mask) 1 through to 127 'B-class' (16-bit mask) 128 through to 191 'C-class' (24-bit mask) 192 through to 223

192.168.36.10 and 200.100.16.3 are both using their traditional 24-bit mask so haven't been subnetted.
1st usable what? The actual subnet is "131.64.16.128"

Host addr's are 131.64.16.129 through to 131.64.16.254 Broadcast addr is 131.64.16.255 Next subnet is 131.64.17.0

BernieM

Reply to
BernieM

Real World: There is nothing *wrong* about using subnet zero, it will work just fine BUT you need to be careful about always specifying masks as otherwise it can get confusing.

As an example, you have /16 network 111.11.0.0 allocated to you.

You design your addressing scheme such that the first two bits available indicate the region (you have four) then the next four indicate which building and the last two in this octet indicate the floor.

So that means 111.11.0.0 /16 is the whole network. 111.11.0.0 /18 is the first region, 111.11.0.0 /22 is the first building and 111.11.0.0 /24 the firat floor within it.

That will work, but if you are not careful it can get VERY confusing, so if you can it is good to avoid subnet zero.

Reply to
Paul Matthews

My fault

1st usable what? The actual subnet is "131.64.16.128" I should have wrote it is > > Sorry,my fault-that is the correct answer -is it because .11 is the
Reply to
gregg johnstone

In reality it doesn't matter at all what the default gateway is assigned. You could assign the middle host address. It comes down to manageability and best practice to avoid confusion but achieve consistency.

I've found the most common practice is to assign the last host as the gateway. Quite often this might be a HSRP virtual address with the 2nd last and 3rd last addresses assigned as real addresses to the primary and secondary gateways.

BernieM

Reply to
BernieM

good

Reply to
jameshanley39

thx for the advice -can you explain what you have written please?

I've found the most comm> Paul Matthews wrote:

Reply to
gregg johnstone

Within a subnet there are two common practices - first or last as DG. Personally I prefer first, but that is just a preference.

What I like to do is .1 - HSRP, .2 first real .3 secong real. If the network is a transit network with firewalls, the convention we are settling on is firewall vrrp last, then the previous two for real firewalls.

Reply to
Paul Matthews

thanks

Reply to
jameshanley39

Greg,

Post always on the bottom, buddy. Unless, you are really angry or mad :)

The Dude

Reply to
The Dude

At least take prime number as host address for 0/0 :-)

FW

Reply to
NO_spamm

Will do :)

Reply to
gregg johnstone

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