Subnetting Question

[acl03]

I kind of asked this question in another post, but i think it deserves its own thread.

I should start by saying I know practically nothing about subnetting.

On our network, we use IP addresses that always start with the same two numbers, regardless of site.

The last two numbers vary.

For example:

Site A: 10.0.1.x
Site B: 10.0.24.x
Site C: 10.0.145.x
and so on...

We always use a 255.255.0.0 subnet mask on our pc's.

When i set up a subnet to associate with a site in AD Sites & services, should i be using the same mask that I do on our PC's (255.255.0.0)? Or should i be using 255.255.255.0?

Thanks.



Thanks,
Andrew

 

[nsantin]

How are these sites interconneted? I would think you need a subnet of 255.255.255.0 with the gateway being the respective router.

As an FYI, subnetting is basically identifying the local addresses that do not need to be routed to be reached.

 

[acl03]

What do you mean how are they interconnected?

What about the "address" portion of the subnet? What does that mean?



Thanks,
Andrew

 

[Steve Bowman]

Subnetting

The subnet mask just defines what is local to me the "Network Interface" what ever this is.

When I attempt network conversation the process looks at my IP Address and Subnet Mask then decides a route. If the address I am going to falles outside my subnet it just send the request to my gateway to be handled. if the request is decided to be local I talk right to the wire.

so by your example
Site A: 10.0.1.x
Site B: 10.0.24.x
Site C: 10.0.145.x
with 255.255.0.0 every one would be LOCAL
as in 10.0.xxx.xxx
now in your situation and using the 255.255.255.0 mask your DC would need to have the Network Interface Muilt Homed with
10.0.1.xxx/255.255.255.0
10.0.24.xxx/255.255.255.0
10.0.145.xxx/255.255.255.0
basically you really have 1 subnet 10.0.xxx.xxx because of the netmask of 255.255.0.0
if you changed the netmask to 255.255.255.0 then only
10.0.1.xxx could talk to 10.0.1.xxx without router/gateway intervention.



Steve Bowman
Independent Technology, Inc.
CA, USA