How to prevent address exhaustion from Secondary Server in split-scope deployment

re: How to prevent address exhaustion from Secondary Server in split-scope deployment

ryan15 — Mon, 22 Aug 2011 18:20:18 GMT

Lets say you have 500 IP's being handed out by 2 DHCP servers runing split 80/20 scopes. During the morning as clients are booted up and doing DHCP discovery, the 80% client goes offline for whatever reason. This would force all clients to get IP's from the 20% scope and would exhaust all IPs frmo the 20% scope. How do you now force those clients to renew their IPs from the 80% and not the 20% without stopping the DHCP Server Service on the 20% server?

Also, how do you handle reservations? With 2 servers, you now have to add the reservation on both DHCP servers?

I'm starting to think that split scope is added complexity that is not needed.

re: How to prevent address exhaustion from Secondary Server in split-scope deployment

Alex — Fri, 29 Apr 2011 08:15:33 GMT

What's the value for the delay configuration?

All thanks

re: How to prevent address exhaustion from Secondary Server in split-scope deployment

mallettero — Thu, 27 Jan 2011 19:03:25 GMT

I'm having this exact problem, however our DHCP is set up on two 2008 Enterprise servers, not R2. We have several split scopes working, except one. In this particular scope, the secondary (70/30) is leasing IP's and we're running out. When we reach our limit, server 1 isn't picking up the slack. First, why isn't server 1 providing addresses first, and how can we avoid running out of addresses? I know we could add more, but that just seems to mask the problem. Can we use configuration features described in R2 manually, somehow? We do not have any exclusions set up.

Thanks!

Bob Mallette

Systems Admin

Davidson County Community College

rmallet@davidsonccc.edu

re: How to prevent address exhaustion from Secondary Server in split-scope deployment

Marc Denman — Mon, 08 Nov 2010 21:47:12 GMT

I am interested in how this might work instead of 80/20 rule type setup and basically in a 100/100 setup between the Primary and Secondary server. In theory, it seems would work the same. However, I am interested in possible caveats that could result from this? Would it even work?

Also, does Microsoft have plans to change up the way DHCP is delievered? Perhaps moving from the current "single instance" Jet database to something that is "known by all participating DHCP" servers would be much nicer. Maybe utilizing ADLS or even moving this to similar design as DNS the replicates in its own AD partition? We are facing more pressures to offer a HA/Redundant solution that will require 'little interaction' in teh event of a failure. Products which our network team looks at are Cisco's CNR and things like InfoBlox appliances.

Thanks!

Marc Denman

Sr. Systems Support Specialist

Global IT Infrastructure

Alticor, Inc.

marc.denman@alticor.com