AD Sites and Services

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I reviewed the "Working with Active Directory" and was curious about the subnet part. I think Mike mentioned that each site that has the DC, you have to put in the subnets. My question is if you can use a summary address for it instead of listing all the subnets of that site?

My second question is if you go into the NTDS Settings and right click the server and select properties, you have a "Change Schedule" where you can replicate up to 4 times an hour. What is the difference between that setting and the IP "Defaultipsitelink" in the inter-site transports where you can change the replication there as well?

Hey Nicholas,

The answer to your first question is tricky. You can use a summary address for a site that has multiple subnets. You will need to monitor this configuration and make sure everything is working as expected. While this method will work, it's officially unsupported by Microsoft. There are a few issues reported with SCCM not working correctly using supernetting. I would watch your logon traffic and make sure clients are being assigned to the correct site.

When you access the properties of the defaultipsitelink,, the schedule indicates whether or not replication is allowed at those times, but not the frequency. This would apply to all replication that occurs across that site link. When you look at the NTDS site settings properties, this controls how often domain controllers in that site attempt to replicate. Once an hour is the default. This only applies to the domain controllers in that site, as it is a per site setting. If the site settings say to replicate twice an hour, but the defaultipsitelink settings are set to no replication for that hour, then they will not replicate.

Hope this answers your questions, if not, let me know.

Mike