Subnet Mask Question

[NewBoy]

Hi Guys,

 

One quick question please I noticed today that the static IP of one of our schools servers has a subnet mask of 255.255.240.0 with a 10 address for the IP, but the subnet mask in DHCP is 10.0.0.0 will it cause any issues on a Server 2012 R2 domain with windows 7 clients ??? Should I leave it as is or will it cause issues ???

[twin--turbo]

Sorry could you clarify?

 

A subnet mask of 255.255.240.0 is not brilliant but not bad. But a mask of 10.0.0.0 if it even exists is insane.

 

TT

[NewBoy]

Sorry my mistake the subnet mask in DHCP is 255.0.0.0 but the static on the server is 255.255.240.0 does it matter at all ??

[FN-GM]

as Twin Turbo says, you can't have a subnet mask of 10.0.0.0 , that isn't possible.

[twin--turbo]

Sorry my mistake the subnet mask in DHCP is 255.0.0.0 but the static on the server is 255.255.240.0 does it matter at all ??

 

So the clients for the subnet get 255.0.0.0,

 

It will work, but it's horrid.

 

And your delivered address ranges would have to be within the 255.255.240.0 scope for all the clients to reach the servers ( if they are within that subnet) ...

 

I work with /24 (255.255.255.0) or less ... Any network that can support that model is under invested.

 

TT

[Jamo]

 

snip

 

And your delivered address ranges would have to be within the 255.255.240.0 scope for all the clients to reach the servers ( if they are within that subnet) ...

 

 

 

 

Not strictly true as the clients would assume the server is within their subnet they would send the traffic directly to the server IP which would resolve using ARP. The server in turn, if the client is out of its subnet, would forward the request to its default gateway, which I'm assuming would be the same router which the rest of the clients would attach to. This would then work, but it is however.... weird.

 

A /8 subnet is just huge, again it will work, but its just wasteful from a VLAN perspective.

[NewBoy]

the ip range is a 10.50.50.0 range and I think i may change the subnet to what it should be for peace of mind at least.

[Jamo]

Be mindful of changing the subnet mask without knowing what you are doing. Make sure your router is also configured with a matching mask else you risk losing all broadcast traffic to your stations.

 

Also make sure the range is capable of addressing all clients else you will end up with address starvation