subnet mask 1

[Jomama46]

What would be the effect of setting a printer with a class b IP and a class C subnet mask?
I ask because these settings were given to me by a companys "IT guy" for their new printer. I reminded him of the discrepancy but he says that that is the way they always do it. The job doenst come up 'til Tuesday so I thought I'd see what you guys say about it. I dont argue with a customer until I've been paid.
The IP is in the private range. 172.16.1.100.and the snm he wants is 255.255.255.0.

Jomama

 

[jimbopalmer]

a subnet mask of 255.255.255.0 just means the printer expects a router to get from 172.16.1.0 to 172.16.2.0 (or other subnets of 172.16.0.0)

It will only talk to devices in 172.16.1.0 without looking for a router.

I tried to remain child-like, all I acheived was childish.

 

[Jomama46]

Right, thanks

Jomama

 

[KiscoKid]

Basically they are performing VLSM which is good practice regards to smarter allocation of address space and it reduces broadcast traffic too.

 

[Jomama46]

vlsm Variable Length Subnet Mask. Interesting,Kisco, can yu expand on that?

Jomama

 

[KiscoKid]

VLSM allows an organization to use more than one subnet mask within the same network address space. Implementing VLSM is often called subnetting a subnet. It can be used to maximize addressing efficiency.

So instead of deploying, for example, point to point links within the 172.16.x.x network and using its classful subnet (255.255.0.0), you can instead subnet this subnet further and use a 255.255.255.252 subnet.

If you'd continued with using a 255.255.0.0 subnet on a point to point link, that would mean you are creating a subnet that can support up to 16000 or so hosts but you only require 2 as it's a point to point. This results in a massive loss of available address space.

VLSM overcomes this by allowing you to further subnet the 255.255.0.0 subnet to create a subnet that only supports the 2 hosts required (255.255.255.252)

Hope this helps

 

[Jomama46]

Good explaination. Thx

Jomama