Generic PTR Pattern

Catches IPs whose PTR hostname looks like it belongs to a dynamic / consumer IP range. These ranges are routinely rejected by mail receivers regardless of any other configuration.

Your hostname doesn't need to look "professional," but if it contains tokens like dynamic or dhcp, or embeds the IP itself in the name, mail servers will treat the IP like a residential customer connection.

Applies to: IPv4 and IPv6 hosts.

How It Works

1. We do a PTR lookup on the IP.
2. For each PTR returned, we match it against a list of regex patterns.
3. If any PTR matches one of the patterns, the check fails.

The default pattern list catches the most common dynamic / consumer naming conventions:

• dynamic
• dhcp
• pool
• cable
• dsl
• client
• customer
• static-customer
• IP-embedded names like 1-2-3-4.example.net

Fails On

• Any PTR matches one of the generic patterns.
• No PTR record published for the IP.

Related Checks

• Reverse DNS (rDNS) - verifies the IP has any PTR at all.
• PTR Hostname Format - flags malformed PTR hostnames; independent of this check.