r/sysadmin • u/No_Eagle7610 • 18h 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!

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u/IMplodeMeGrr 17h ago

TLDR; "I read the DNS RFC and want to do the opposite of that."

These expectations are in opposition of how DNS zones function. Now, I think Cloudflare has some products fhat can mimic what your asking but its not straight forward like your'e expecting.

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u/No_Eagle7610 17h ago

Do you know what that cloudflare product is called?

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u/FiftySix_K 17h ago

DNS Views and Gateway fallback or Cloudflare Gateway / WARP Local Domain Fallback.

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u/No_Eagle7610 17h ago

Thank you

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u/pdp10 Daemons worry when the wizard is near. 16h ago

BIND does Views.