Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

DHCP Scope Conflict

Posted on 2007-04-03
6
Medium Priority
?
1,171 Views
Last Modified: 2012-05-05
Hello All- I am attempting to set up a new DHCP scope and encountering the
error message "The address range and mask conflict with an existing scope."
The scope I am attempting is 192.168.150.210-234. The existing scopes are on
two different servers: Server1 Scope 192.168.150.20-74, and Server2 Scope
192.168.150.75-124. All scopes are /24. I was able to set up the two existing
scopes with the same mask, but do not understand why an additional scope on
Server2 (Windows 2k3) is producing this error. Any ideas why I am encountering this error?

Thanx

0
Comment
Question by:ahrimann
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
6 Comments
 
LVL 7

Expert Comment

by:LimeSMJ
ID: 18847563
By design, Windows DHCP can only serve one scope per subnet.  The reason why the Server1 and Server2 live happily on the LAN with the same subnet is because there is no overlap... whereas trying to add additional IPs to Server2 on the same subnet violates the "one scope per subnet rule".  What you are trying to do must be done using IP exclusions within the scope on Server2.  

On Server2, you need to change the original scope to encompass the start and end point for the DHCP scope space you desire:  Start would be 192.168.150.75 and end would be 192.168.150.234.  You would then add a rule to exclude 192.168.150.125 to 192.168.150.209.  Note: It is best practice to deactivate, delete and create a new scope instead of just increasing the address space on an existing scope, otherwise your clients may experience NACKs on DHCP requests.
0
 

Author Comment

by:ahrimann
ID: 18851828
Thanx for the heads up. If I wanted to distribute these excluded addresses (.210-.234) to a specific group of hosts (IP phones actually), how would I go about doing that?
Thanx
0
 
LVL 7

Accepted Solution

by:
LimeSMJ earned 1000 total points
ID: 18854388
Real easy... Setup DHCP Reservations.

All you would need to do is find out the MAC address of each phone and reserve them positions in your scope.  Just do a Create Reservation and everything is self-explanatory within the window that pops up.

Just another tip... if the phone doesn't have the MAC address listed on a label somewhere, just plug it into your network and in your Address Lease list, you can find the MAC address that way.  Just remember that once the Reservation is set, you will have to power cycle the phone (or just disconnect and reconnect it from the network) to get the new Reserved IP.
0
What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

 
LVL 7

Expert Comment

by:LimeSMJ
ID: 18854411
Oh I forgot to mention, if you have more IPs than phones and want to restrict that IP space exclusively for phone usage, a simple way to do it is by assigning a local MAC address (just a random hexadecimal with length 12 BUT the last digit is 1... ie: ab-04-00-c3-00-01).  Chances of you typing in a actual working MAC address on your network is 1:281,474,976,710,656.  :)
0
 

Author Comment

by:ahrimann
ID: 18854467
Thanx LimeSMJ- I did figure this out, but I was hoping there was a way to do it dynamically. Ah well, more job security I suppose...
;)~
0
 
LVL 7

Expert Comment

by:LimeSMJ
ID: 18854490
I wish there was too.  Someone needs to make a utility so that you can just right click on an existing lease and convert it to a reservation.

Thanks for the points.
0

Featured Post

NFR key for Veeam Agent for Linux

Veeam is happy to provide a free NFR license for one year.  It allows for the non‑production use and valid for five workstations and two servers. Veeam Agent for Linux is a simple backup tool for your Linux installations, both on‑premises and in the public cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The Need In an Active Directory enviroment, the PDC emulator provide time synchronization for the domain. This is important since Active Directory uses Kerberos for authentication.  By default, if the time difference between systems is off by more …
ADCs have gained traction within the last decade, largely due to increased demand for legacy load balancing appliances to handle more advanced application delivery requirements and improve application performance.
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
Is your data getting by on basic protection measures? In today’s climate of debilitating malware and ransomware—like WannaCry—that may not be enough. You need to establish more than basics, like a recovery plan that protects both data and endpoints.…

610 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question