Active Directory Replication

Posted on 2006-06-01
Last Modified: 2010-04-18
Hello Experts,

I wnat to have a backup server on a remote location (other netowork) for our ERP server. For this purpose I restored from a complete backup the whole system on a new server. The Server is running WIn 2003 and is a domain controller. I want this two servers (backup server and production server) replicate their Active Directory and the SQL server database. My question is what do I need to do in order to have this two server replicate their AD one to another, taking into account that I have two server exactly the same installation, same computer name, in two differrent networks.

Please help.

Question by:ImmanuelUlmer
    LVL 48

    Expert Comment

    Hi ImmanuelUlmer,

    you will come accross issues with your naming and ip addressing

    what kind of connection do you have between the two, are they currenty two different domains?
    LVL 16

    Expert Comment

    Because the 2nd server is a clone of the original server, therefore has the same Unique Identifier, it's not going to be possible to replicate AD between server 1 and 2.
    You'll need to install a new server and add it to the domain as DC (dcpromo), and define AD Sites for the 2 subnets to enable replication.

    Author Comment


    I have currently an exact copy, I think they make relpication between th AD. I opened a user in one domain controller, and he showed up after some time in the other (I need double check this). I didn't configure any replication, but I think it does it. Is this logical? How can I check if they should make replcation or not?

    Physically the two server are seperated by a router.

    thanks so far,


    Author Comment


    Just to clarify, the two servers have the same system name.
    The IP Addresses are of differrent networks.

    Author Comment

    Hello RedWulf,

    I want to avoid to install the server from scratch, because I don't want to go into the ERP INstallation, which is very complicated.
    Is there a way to recreate the AD with another identifier?

    thanks for your help,
    LVL 16

    Accepted Solution

    There is NO WAY they can be replicating in the current situation.
    Replication can be checked with ReplAdmin and ReplMon tools from the Support tools (from the Windows CD rom \SUPPORT folder).
    LVL 15

    Assisted Solution


    Here are the steps I would suggest
    ServerA is you first main server
    ServerB is backup at the remote location - the exact copy of serverA

    If the machine is an exact copy with same computername then there is NO WAY AD replication is working.
    If AD replication is working and creating a user on one replicates to the other you do not understand the configuration. ( goto command prompt on each and type hostname) (there are some products which swap computername on failure like NSI Software's DoubleTake )

    Stop/prevent routing between the two
    On server B, run dcpromo - demote the server - get it to be in a workgroup
    Rename Server B's computername
    Run NewSid from Sysinternals - the computer will have the same sid as the first one
    Start/enable routing
    On Server B join it to the domain
    reboot server b
    On server B run dcpromo to add a DC to an existing domain.
    check the 3rd patry services, any services on Server A - local accounts on domain controllers are "domain accounts"
    Check services on Server B and make sure all start with the proper accounts, etc.
    now you have AD working between the two.

    Now sure what ERP app this is where you want to research options for recovery of that - maybe at the point of failure change the name of the server B - but if/when you wanted to bring server A into the picture that would be a problem.

    If having seperate physical servers for ERP and AD is a problem for AD/ERP recovery think about MS Virtual Server or VMware for the AD Domain Controllers running as guest.


    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    IT, Stop Being Called Into Every Meeting

    Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

    I guess it is not common knowledge to most Wintel engineers/administrators: If you have an SNMP-based monitoring system in your environment (and it's common to have SNMP or Syslog) it's reasonably easy to enable monitoring of the Windows Event logs,…
    Recently, I had the need to build a standalone system to run a point-of-sale system. I’m running this on a low-voltage Atom processor, so I wanted a light-weight operating system, but still needed Windows. I chose to use Microsoft Windows Server 200…
    Need more eyes on your posted question? Go ahead and follow the quick steps in this video to learn how to Request Attention to your question. *Log into your Experts Exchange account *Find the question you want to Request Attention for *Go to the e…
    This video discusses moving either the default database or any database to a new volume.

    760 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

    14 Experts available now in Live!

    Get 1:1 Help Now