2 DCHP scopes under superscope.  New scope stopped working

Posted on 2015-01-28
Last Modified: 2015-05-05
We have 90 computers, 90 VOIP, 20 printers.  We had 0/24 and DHCP was running out, so I bought another 0/24, but not contigious a few months ago.  Put both under a superscope.

DHCP is on a Server 2003 machine.  

It was working fine for a number of months, but now any computer under the 2nd new scope isn't working, or working intermittently.

Side strange thing - we had a Cisco Access Point for a while before I got a large Ruckus install.  It was called PMG-1040, and that is coming up on some people's machines that are hard wired as the domain in the lower right icon.  I removed that access point months ago.

I reserved a bunch of the 1st scope and now static on some people's machines so they can work (as we are only dipping into 2nd scope for about 10 people), but its a problem i have to solve quickly.

Any advice?   (i don't understand VLAN usage or different subnet usage - but open to learning).

Thanks guys!
Question by:jackharkness
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Expert Comment

by:Craig Beck
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So you had a /24 with 90 computers, 90 voip devices and 20 printers.

A /24 gives you 254 addresses.
90+90+20 = 200

You shouldn't need another /24 for this (forgetting the wireless bit for a minute).

Can you show us what your network looks like please?
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Expert Comment

by:Steve Knight
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Are these all public internet IP's for each internal user then too (you say you bought some more)?

You would not normally want a superscope, just two scopes in DHCP, the ip helper/dhcp helper on your core switches would point to the DHCP server. and users on the different subnets/vlans would communicate through the core switch.

As has been said above you need to give some more info. on network structure etc. I think before we can do anything but guess.

Author Comment

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Thanks guys for your comments.  

We have a Ruckus Wireless, and almost everyone has an iphone, and they also sometimes walk around with their laptops to conference rooms, etc.

Here is my setup:
-Mikrotik Router
-PDC on Server 2003
-DHCP/WINS on separate Server 2003
-DNS on a CentOS
-Exchange 2013 on Server 2012
VOIP is hosted through our ISP, and we have POE polycoms that have the computers plugged into them (and they are plugged into the Cisco/Linksys switches).

We had a for years, but were running out of space.  I obtained (through ISP) and added it under DHCP, but I only could do it as another scope and put them both under a superscope.

Its been that way for 6 months, and now suddenly people who have their Windows 7 Pro machines - when they have a .36,xxx, they can't get internet and/or network access, and its intermittent.  

I'll continue to research what you wrote in your comments, but wanted to get this posted as you asked for a network description of what we have.

Thank you guys!
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Author Comment

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Anyone?  I am a little clueless.  I'm evening willing to pay for an answer...  as this is causing a lot of problems.

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Expert Comment

by:Steve Knight
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Well getting dhcp address in the first  place and what accesses are separate  of course.

When you say intermittent , what is?

Are there any vlan defined, if not then just one lan that has two ranges of ip on it, reserved addresses would get specific address, otherwise random which subnet.

How do both of these communicate with each other , through the Internet gateway presumably?

Could you show us ipconfig /all from machine with each type of ip address pls?


Accepted Solution

jackharkness earned 0 total points
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I figured out the problem.... which was during setup of the second scope, and included the x.x.x.1 in the DHCP handout (when it should have only handed out .2-.254)... so i had a .1 as a gateway and some lone netbook that sat in a corner plugged in but never used had grabbed the .1 and was receiving requests but ...  

The downside is it took so much time and effort to figure out what was wrong... i even had my advanced network guy stare at screenshots, but we all missed it for so long...

Anyway, thanks for advice... this is now closed thank goodness.

Author Closing Comment

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There were so many possible problems that it could have been, and it ended up being just a typo in the DHCP setup in Windows Server.  Yikes.

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