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DHCP: How do you configure a class B scope to support the maximum hosts.

I at work we use a class B network address 172.16.0.0.
My manager has configured a scope in dhcp. The range of the scope is 172.16.1.1 - 172.16.1.254.
The addresses in this scope are over 90% used so my  manager created a superscope with the second scopes range being 172.16.2.1 - 172.16.1.254. All of the above addresses use the default subnet mask 255.255.0.0.

Now we are having problems with this superscope setup as hosts renewed on scope B for testing cannot ping servers on the original scope.
I believe a relay might correct this issue?

I was under the impression that a class B address could support 65534 hosts on a single network address.
Can anyone advise me how this is done and can be configured for the network at work?


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gpersand
Asked:
gpersand
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2 Solutions
 
gpersandAuthor Commented:
Sorry the second scopes range is 172.16.2.1 - 172.16.2.254
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Netman66Commented:
If you are using the B-class subnet mask, then make the original scope 172.16.1.1-172.16.2.254 and put in your exclusions for static devices.

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joedoe58Commented:
Since you have a b-class net mask you can use the full range from 1-254 in the third octet so there is no need to separate into superscopes or anything else.
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gpersandAuthor Commented:
Netman66 : Are you implying using only 1 scope and how many addresses will your range lease?

Joedoe58:  Sorry but I dont think I fully understand what you are asking me to do.  Could give a scope example such as the one Netman66 gave please.
I would also be grateful for a basic explanation of how to use the range from 1-254 in the third octet so there is no need to separate into superscopes or anything else.
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gpersandAuthor Commented:
Why is what my manager did wrong?
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Netman66Commented:
Yes, 1 scope.

Since you are using a B-class subnet mask you actually have 172.16.1.1 to 172.16.255.254 that will be on the same network.

Creating 2 scopes that are technically in the same network isn't really the way to do this.  You want to extend your original scope to give you more addresses.

Using more than one scope is most normally used for 2 or more different subnets.

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joedoe58Commented:
I agree with netman66. You would only create more than one scope if your clients were separated with a different net mask. For example if you used the mask 255.255.255.0 then you would have to set up two scopes one for 172.16.1.x and 172.16.2.x and so on, but in your case that is not necessary since your mask contain all addresses.
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gpersandAuthor Commented:
The given solution will be tested in Friday.

Is there any way I can simulate eg1000 dhcp clients to test the scope myself?
I am limited to 1XPclient and 1DC connected by a Cat 5 network cable.
Is there a way or even 3rd party software I can use for testing dhcp.
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gpersandAuthor Commented:
on Friday......
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Nirmal SharmaSolution ArchitectCommented:
Very Simple....if you are using a Class B network and have more than 254 hosts then do the subnetting and supernetting. By using subnetting and supernetting client will receive IP Addresses from the second scope but SAME Subnet mask so they can ping and access network resources.
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gpersandAuthor Commented:
The Friday test unfortunately did not take place last Friday.  I have been informed it will take place this Friday.
Sorry if an acceptence was expected.

Systmprog: Can you elaborate on your answer?
                 What are you asking me to do in steps?

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Nirmal SharmaSolution ArchitectCommented:
I want you to do a supernetting. In which you need to give only one subnet mask in each scope and different IP Addresses range which relates to this subnet mask derived from supernetting. Because you create two scopes with two different subnet mask and IP address so when clients receive IP addresses they also get the different subnet mask hence not reachable problem and can't contact to each other. So to resolve this problem you go through this way:  -

A detailed example here: -
http://www.tcpipguide.com/free/t_IPCIDRAddressingExample.htm
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Netman66Commented:
Sys, he has run out of IPs in the main scope.  He really doesn't need two subnets - simply extending the scope will do.  His subnet mask will all him to redefine the existing scope with no problems.  In his case, supernetting is not necessary at all.

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gpersandAuthor Commented:
Sorry for the late reply. I have recently moved home and jobs.
The solution you gave me worked. Thanks for your expert knowledge.
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