DHCP Windows 2008 R2 problem

[nickjean]

I want to put a new DHCP Server with IP 192.168.0.0 and subnet mask 255.255.252.0 that would give me following IP-Range

 

192.168.0.1 - 192.168.0.255

192.168.1.1 - 192.168.1.255

192.168.2.1 - 192.168.2.255

192.168.3.1 - 192.168.3.255

 

My question is: Have I to define 4 Scopes? If yes which Subnet mask should I use for each scope?

 

I did try to put 4 scopes but it does not work. My first scope is called 192.168.0.26 until 192.168.0.200 with subnet mask 255.255.252.0

But if want to define the secound scope with 192.168.1.26 until 192.168.1.200 with subnet mask 255.255.252.0, I get a error message:

 

" the address range and mask conflict with an existing scope".

 

Does it correct step? Or do I make a mistake

 

Thanks for help

 

Nick

[sabe75]

Just create a single scope of address range 192.168.0.0/22 mask 255.255.252.0 and create exclusions / reservations for your servers.

 

Kind Regards

 

Sabe75

[nickjean]

Hi,

 

Thank you for your answer. But I dont understand you. I should create a single scope with 192.168.0.0 until 192.168.0.254 subnet mask 255.255.252.0

And what is happening withe othe range 192.168.1.1 and 192.168.2.1 and 192.168.3.1? I need 1024 hosts. Your descrition I only will have 254 hosts

 

Regards

 

Nick

[sabe75]

Create one scope of 192.168.0.0/22, the 22 means subnet mask 255.255.252.0. Therefore a scope of 192.168.0.0 with that particular subnet mask includes:

 

192.168.0.0-192.168.0.255

192.168.1.0-192.168.1.255

192.168.2.0-192.168.2.255

192.168.3.0-192.168.3.255

 

The reason being that the 252 in the third octet converts to 11111100, the two 0's represent are the decimal figures of 2 & 1 going left to right and become part of the host section of the address, meaning you can have networks 0,1,2 & 3 (1+2) in the third octet (place of dots) as part of the same network, as normally a classfull 'C' class address would be 255 and therefore binary 11111111 (ones in the mask represents the network part of the address as opposed the host/computer). The technique is called supersubnetting, e.g. adding multiple networks together (as one).

 

Kind Regards

[sabe75]

Create one scope of 192.168.0.0/22, the 22 means subnet mask 255.255.252.0. Therefore a scope of 192.168.0.0 with that particular subnet mask includes:

 

192.168.0.0-192.168.0.255

192.168.1.0-192.168.1.255

192.168.2.0-192.168.2.255

192.168.3.0-192.168.3.255

 

The reason being that the 252 in the third octet converts to 11111100, the two 0's represent are the decimal figures of 2 & 1 going left to right and become part of the host section of the address, meaning you can have networks 0,1,2 & 3 (1+2) in the third octet (place of dots) as part of the same network, as normally a classfull 'C' class address would be 255 and therefore binary 11111111 (ones in the mask represents the network part of the address as opposed the host/computer). The technique is called supersubnetting, e.g. adding multiple networks together (as one).

 

Kind Regards

 

Here is an example of what you want I have excluded the first 9 addresses.

 

Kind Regards

[nickjean]

Hi Sabe75,

 

Thank you very much for your replay.Now I can understand you what you mean.Are you sure if I create a scope of 192.168.0.0/22 that particular IP-Range is included? I mean if I create a scope with for example:

 

192.168.0.30 until 192.168.3.200 /22, would I have 1022 hosts? Have I to create a DHCP Relay Agent too or not? I think yes

 

Kind Regards

 

Nick

[sabe75]

Hi Sabe75,

 

Thank you very much for your replay.Now I can understand you what you mean.Are you sure if I create a scope of 192.168.0.0/22 that particular IP-Range is included? I mean if I create a scope with for example:

 

192.168.0.30 until 192.168.3.200 /22, would I have 1022 hosts? Have I to create a DHCP Relay Agent too or not? I think yes

 

Kind Regards

 

Nick

Yes, the ranges 192.168.0-3 are one network because of the mask, they have effectively been added together. You do not need a relay agent as they are not on different networks, unless you have some sort of router between. Please try as is, am sure you will see if will work fine. In my previous network, I actually used that exact subnet. So you are effectively creating a scope from 0.31 --> 3.200 making 254-30=224 on your 0 range, 254 on your 1 and 2 range and 199 on you 3rd. Therefore, 224+254+254+199=931 (remember to exclude the 0 & 255 addresses as these would have been typically used for network ID and broadcast on classfull).

 

Kind Regards

[sabe75]

Yes, the ranges 192.168.0-3 are one network because of the mask, they have effectively been added together. You do not need a relay agent as they are not on different networks, unless you have some sort of router between. Please try as is, am sure you will see if will work fine. In my previous network, I actually used that exact subnet. So you are effectively creating a scope from 0.31 --> 3.200 making 254-30=224 on your 0 range, 254 on your 1 and 2 range and 199 on you 3rd. Therefore, 224+254+254+199=931 (remember to exclude the 0 & 255 addresses as these would have been typically used for network ID and broadcast on classfull).

 

Kind Regards

 

PS. Could you vote for me, to give me some good reputation.

[nickjean]

Hi again,

 

Thanks for replay. I am not sure that I dont need a DHCP relay agent. I can remember that MS has recommed me to do it.

Here is the message from Microsoft:

 

###################

Yes, we need to create 4 DHCP scopes, one for each subnet. To do so, we also need to configure DHCP relay agents for each subnet.

Generally speaking, there are two ways to configure DHCP relay agents .First, to configure routers act as a configure DHCP relay agents. In most cases, routers support DHCP relay. If your routers do not, contact your router manufacturer or supplier to find out if a software or firmware upgrade is available to support this feature.Second, we can configure a computer running Windows Server® 2008 to act as a relay agent by installing the DHCP Relay Agent service.

########################################

 

What do you mean about this resulotion?

 

Regards

[sabe75]

Hi again,

 

Thanks for replay. I am not sure that I dont need a DHCP relay agent. I can remember that MS has recommed me to do it.

Here is the message from Microsoft:

 

###################

Yes, we need to create 4 DHCP scopes, one for each subnet. To do so, we also need to configure DHCP relay agents for each subnet.

Generally speaking, there are two ways to configure DHCP relay agents .First, to configure routers act as a configure DHCP relay agents. In most cases, routers support DHCP relay. If your routers do not, contact your router manufacturer or supplier to find out if a software or firmware upgrade is available to support this feature.Second, we can configure a computer running Windows Server® 2008 to act as a relay agent by installing the DHCP Relay Agent service.

########################################

 

What do you mean about this resulotion?

 

Regards

 

Okay, if you want the range of 192.168.0.0 not to see 192.168.1.0 or 2.0 or 3.0 etc... as in four separate scopes/networks then you you need to create 4 scopes with the mask 255.255.255.0 for each (class C) and use a DHCP relay as these are segmented at layer 3, e.g. will need a router to communicate (layer 3). However, if you want these to be one address range with the mask 255.255.252.0 and therefore they all see each other with not router, only switches (layer 2) between the server and the clients then you do not need a DHCP relay agent and require only one scope.

 

I think it would help if you described your network infrastructure a little more, this would probably make your requirement clearer.

 

Kind Regards