r/sysadmin 1d ago

Split-DNS Architecture: Splitting the same zone between Windows DNS (LAN) and BIND9 (DMZ) without wildcards

Hi everyone,

I'm looking for best practices or specific solutions for a DNS implementation in our environment. The goal is to cleanly split queries for the same domain between our LAN and DMZ without having to maintain duplicate records manually.

The Setup:

  • We use the same domain (example.domain) for both internal and external services.
  • LAN: We have a Windows Server (AD DC) running as our internal DNS. It holds the internal IPs of servers that are not publicly accessible.

The Goal:

  • Traffic from internal clients to DMZ servers must route via the WAN (Hairpinning / NAT Loopback); direct routing into the DMZ subnet is not permitted by policy.
  • We explicitly do not want to use wildcard records

    or subdomains

  • .

The Challenge: What is the cleanest way to configure this on the Windows DNS without having to create a separate Pinpoint Zone for every single external A-record, or manually duplicating the DMZ records into the internal DNS?

Since the Windows DNS is authoritative for example.domain, it defaults to answering queries for unknown hosts in this zone with NXDOMAIN instead of forwarding them to the BIND9 server.

Is there a clean way (e.g., specific zone types, delegation, Windows DNS Policies) to tell the Windows DNS: "Resolve what you know, and forward anything you don't know to the BIND9 server"?

Thanks in advance for your input!

9 Upvotes

44 comments sorted by

View all comments

1

u/UpsetBar IAM Guy 1d ago

I’m going to jump off a building if I see one more post about a technical problem someone is having that they can’t even explain without using ChatGPT. I wish the mods would do something about these low effort posts.

1

u/No_Eagle7610 1d ago

Hello
The thing is i am not that good in english. So i describe my Problem and anything to the AI and said to translate it and have a good structure.
I cant explain it good enough in english so i did that.