Solved

Centralized DHCP with similar VLANs in multiple offices.

Posted on 2014-09-29
3
412 Views
Last Modified: 2014-09-29
I am doing some work at a client that has 25 offices.  They have a central DHCP server at the main office.  (We won't go into how that is a bad idea right now.)

Each of the 25 offices have the same VLANS, vlan 110 for data, vlan 120 for voice.  Each office has their own 10.x.x.x/16 IP space.

On each of the VLANs there is a helper IP address for the DHCP server pointing back to the central DHCP server.

My question is this --- how does the DHCP server know when it hears a DHCP for VLAN110 in office A to give an IP from the proper scope and not from the scope VLAN 101 of office B?

I suspect the DHCP server somehow determines this from the source IP of the router/switch that has the help IP configured on it local VLAN.  


Thank you,

Scott
0
Comment
Question by:BladesAway
3 Comments
 
LVL 16

Expert Comment

by:Joshua Grantom
ID: 40350921
Its probably from the router IP at that location and how the DHCP Scopes are setup.
0
 
LVL 24

Accepted Solution

by:
Ken Boone earned 500 total points
ID: 40350946
So if each office has a 10.x.x.x/16 I am assuming that the 2nd octet is unique at each location.  Basically the local router that is performing the DHCP relay to the centralized DHCP server has his address on the local segment in the forwarded DHCP packet.  When the DHCP sees this forwarded packet, he knows what network it was forwarded from based on this and provides the appropriate address assignment.  The DHCP has no idea nor does he care what vlan the remote location is on.

Hope that helps.
0
 

Author Comment

by:BladesAway
ID: 40350969
That' kind of what I was figuring Ken.  Thank you for confirming.

Scott
0

Featured Post

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.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
P2P and MPLS 3 42
Unifi AP 4 50
Booster, Repeater, or Wireless Access Point 9 44
Load balancing - basic design/questions for customer request 4 37
Even if you have implemented a Mobile Device Management solution company wide, it is a good idea to make sure you are taking into account all of the major risks to your electronic protected health information (ePHI).
Most of the applications these days are on Cloud. Cloud is ubiquitous with many service providers in the market. Since it has many benefits such as cost reduction, software updates, remote access, disaster recovery and much more.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…

910 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

Need Help in Real-Time?

Connect with top rated Experts

25 Experts available now in Live!

Get 1:1 Help Now