In Active Directory environments, the relationship between DNS records and domain controllers (DCs) often causes confusion. Let's break down the typical setup:

; Traditional AD DNS zone example.com
example.com.    3600    IN    A    192.168.1.10  ; DC1
example.com.    3600    IN    A    192.168.1.11  ; DC2
_ldap._tcp.dc._msdcs.example.com. 3600 IN SRV 0 100 389 dc1.example.com.

Active Directory clients primarily use SRV records (not A records) to locate domain controllers. These special records are automatically created in the _msdcs subdomain:

• _ldap._tcp.dc._msdcs.example.com points to DCs
• _kerberos._tcp.dc._msdcs.example.com handles authentication
• _gc._tcp.example.com manages global catalog lookups

To safely transition your A records to point to web servers:

; Before
example.com.    IN    A    192.168.1.10  ; DC1
example.com.    IN    A    192.168.1.11  ; DC2

; After
example.com.    IN    A    203.0.113.45  ; Web server
dc1.example.com. IN    A    192.168.1.10  ; Explicit DC record
dc2.example.com. IN    A    192.168.1.11  ; Explicit DC record

After making changes, test your configuration with these essential commands:

# Verify DC discovery
nltest /dsgetdc:example.com

# Check DNS resolution
nslookup example.com
nslookup -type=SRV _ldap._tcp.dc._msdcs.example.com

# Test authentication
klist get -f EXAMPLE.COM

While this approach generally works, beware of these scenarios:

• Legacy applications hardcoding DC IPs (consider DNS CNAME aliases)
• Third-party integrations that may expect the root domain to resolve to a DC
• Cached credentials during the transition period

If you're uncomfortable changing root A records, consider these options:

; Option 1: Web server redirect
example.com.    IN    CNAME   www.example.com.

; Option 2: Split DNS
; Internal view:
example.com.    IN    A    192.168.1.10
; External view: 
example.com.    IN    A    203.0.113.45

In Active Directory environments, DNS configuration is critical for both domain operations and user accessibility. A common scenario arises when you want example.com to resolve to your web server while maintaining AD functionality.

Contrary to popular belief, clients don't primarily rely on the domain's A record to locate Domain Controllers. Instead, they use SRV records stored in these DNS locations:

_tcp.example.com
_udp.example.com
_msdcs.example.com

These special records contain all necessary information about domain services, including:

• LDAP service locations
• Kerberos servers
• Global Catalog servers

For your scenario with example.com, here's what you can safely do:

; Zone file for example.com
@        IN A      192.0.2.100    ; Web server IP
dc1      IN A      192.0.2.10     ; DC1 IP
dc2      IN A      192.0.2.11     ; DC2 IP

This configuration allows:

• HTTP requests to example.com to reach your web server
• AD clients to find domain controllers via SRV records
• Explicit DC access using dc1.example.com

Before making changes in production, verify your setup with these PowerShell commands:

# Check SRV records
nslookup -type=srv _ldap._tcp.example.com

# Test domain functionality
Test-ComputerSecureChannel -Repair

# Verify DC discovery
nltest /dsgetdc:example.com

While this approach generally works, watch out for:

1. Legacy applications that might hardcode DC lookups
2. Third-party integrations expecting DCs at the root domain
3. Cached DNS records in older clients

If you need absolute certainty, consider these alternatives:

; Option 1: Use different internal/external views
@ IN A 192.0.2.100    ; External DNS
@ IN A 192.0.2.10     ; Internal DNS (DC)

; Option 2: Use CNAME for web traffic
www IN CNAME webserver.example.com.

After working with numerous AD implementations, I can confirm that pointing your domain's A record to a web server while maintaining proper SRV records for DCs is a valid and commonly used configuration. The key is ensuring all SRV records are properly configured and that you've tested authentication flows after making changes.