When configuring DNS records, the interaction between wildcard and explicit CNAME records follows specific precedence rules. The DNS system will always prioritize an exact hostname match over a wildcard match. This means:

*.example.com.    IN CNAME target1.example.com.
specific.example.com. IN CNAME target2.example.com.

In this configuration, queries for "specific.example.com" will resolve to "target2.example.com", completely ignoring the wildcard record. The wildcard only acts as a catch-all for non-matching subdomains.

Let's examine real-world BIND zone file configurations to demonstrate this behavior:

; Zone file for example.com
$TTL 3600
@       IN SOA  ns1.example.com. admin.example.com. (
                2023081501 ; serial
                3600       ; refresh
                900        ; retry
                604800     ; expire
                86400      ; minimum TTL
                )

; Name servers
        IN NS   ns1.example.com.
        IN NS   ns2.example.com.

; Base domain records
@       IN A    192.0.2.1
www     IN CNAME example.com.

; Wildcard configuration
*       IN CNAME fallback.example.com.

; Explicit subdomains override wildcard
api     IN CNAME aws-lb-123.elb.amazonaws.com.
blog    IN CNAME ghost.io.

You can verify this behavior using common DNS tools:

# Testing explicit record
dig +short specific.example.com CNAME
> target2.example.com.

# Testing wildcard fallback
dig +short random123.example.com CNAME
> target1.example.com.

While the basic precedence rule is straightforward, there are some special scenarios to consider:

1. DNSSEC validation must be properly configured for both record types
2. Some DNS providers implement wildcards differently in their UI
3. TTL differences between records don't affect precedence
4. CNAME chains (where a CNAME points to another CNAME) must still follow these rules

Major DNS providers handle this consistently, but their interfaces differ:

// AWS Route 53 JSON representation
{
  "Changes": [{
    "Action": "UPSERT",
    "ResourceRecordSet": {
      "Name": "*.example.com",
      "Type": "CNAME",
      "TTL": 300,
      "ResourceRecords": [{ "Value": "fallback.example.com" }]
    }
  }]
}

Remember that DNS caching can sometimes obscure immediate changes, so always verify with +norecursive queries when testing.

In DNS resolution, there's a clear hierarchy when multiple records exist for the same hostname. The wildcard (*) record serves as a catch-all, but specific records always take precedence over wildcard entries. This behavior is defined in RFC 4592 which specifies wildcard DNS record behavior.

Consider these DNS records configured in a zone file:

; Zone file example
@               IN  A       192.0.2.1
*               IN  CNAME   domain.com
bla.domain.com. IN  CNAME   some.example.com.
www             IN  CNAME   domain.com

In this setup:

• Requests to bla.domain.com will resolve to some.example.com
• Requests to foo.domain.com (non-existent) will resolve to domain.com
• Requests to www.domain.com will resolve to domain.com

You can verify this behavior using dig command:

dig +nocmd +noall +answer bla.domain.com CNAME
dig +nocmd +noall +answer random123.domain.com CNAME

The first command should return some.example.com while the second will show domain.com.

When implementing wildcard CNAMEs with specific overrides:

1. Ensure your DNS provider supports both record types
2. Check for TTL (Time-To-Live) differences which might cause temporary resolution issues
3. Remember that wildcards don't match empty hostnames (just domain.com)

Major cloud providers handle this consistently:

# AWS Route 53 example
{
  "Changes": [
    {
      "Action": "CREATE",
      "ResourceRecordSet": {
        "Name": "*.example.com",
        "Type": "CNAME",
        "TTL": 300,
        "ResourceRecords": [{"Value": "domain.com"}]
      }
    },
    {
      "Action": "CREATE",
      "ResourceRecordSet": {
        "Name": "special.example.com",
        "Type": "CNAME",
        "TTL": 300,
        "ResourceRecords": [{"Value": "other.target.com"}]
      }
    }
  ]
}

Be aware of these edge cases:

• Some DNS implementations may cache records differently
• DNSSEC validation might behave differently with wildcards
• Email-related records (MX) have special wildcard rules