DNS DNAME Record: Migration use case

Just came across a common post-migration scenario that often happens during old Source domain decommissioning: What do we do with Source Domain name? Particularly how to redirect all those old name references to already migrated SERVER.SOURCE.LOCAL which now lives at SERVER.TARGET.LOCAL. It has very easy and elegant solution actually and while I am sure it wouldn’t be anything new for DNS gurus, since I am not the one 🙂 I will write today about DNS DNAME record.

So you decommissioned SOURCE.COM domain and there is no DNS authoritative for this namespace anymore. If there are still old stub or secondary DNS zones – they are no longer pointing to any authoritative DNS servers for that zone. What if there are still some applications in the environment that are trying to reach SERVER.SOURCE.LOCAL and it needs to be redirected to TARGET.LOCAL? The answer is DNAME. It’s like CNAME record, but for Domains.

1. Create Primary Zone for SOURCE.LOCAL in your new Domain DNS environment.

2. Right click | Other Record | DNAME

3. Specify TARGET.LOCAL as a name.

That’s it – 3 easy steps. Now any query for servers in SOURCE.LOCAL Domain would actually hit records in TARGET.LOCAL domain. That includes MX or pretty much any record.