What domain should I use for a PTR record for shared IPs?

Email marketer from Mailjet shares that it's essential to have a PTR record that matches the hostname of your sending server. They emphasize using a subdomain of your main domain to maintain a clean and professional image. For shared IPs, they recommend a consistent naming convention that reflects the service provider's ownership and purpose.

Email marketer from StackExchange explains that for shared IP addresses, the PTR record is usually the responsibility of the ISP or hosting provider who owns the IP range. This is because they control the reverse DNS zone for those IP addresses. The PTR record will typically point to a hostname within the ISP's domain.

Email marketer from Litmus explains setting up email authentication, including PTR records, is a foundational step to improve email deliverability. For shared IPs, the responsibility for PTR records falls on the ESP. The PTR record's hostname should clearly identify the sending server as belonging to the ESP.

Email marketer from WebHostingTalk explains that, for shared hosting or shared IP situations, you won't have control over the PTR record. Your hosting provider or ESP will manage it, and it will typically point to a generic hostname associated with their infrastructure. You should not attempt to set your own PTR record in this scenario.

Email marketer from Reddit shares that with shared IPs, your ESP will manage the PTR record, so you generally don't need to worry about it. They add that it's important to ensure your ESP has properly configured the PTR record on your behalf, which should be the ESP's domain.

Email marketer from SparkPost shares that when using shared IP pools, the PTR record should reflect the IP's owner (the ESP). They recommend not using client-specific domains in the PTR record for shared IPs, instead opting for a generic hostname that identifies the ESP's mail server.

Email marketer from Email Geeks shares that T-Online dislikes PTR records with numeric patterns or parts of the IP address and insists on the PTR record identifying the organization responsible for the message.

Email marketer from SendGrid recommends configuring reverse DNS so the IP address resolves to a domain you control. They highlight that this is crucial for deliverability, and that for shared IPs, this is usually managed by the ESP, who would typically use their own domain.

Expert from Spam Resource explains that if you are using shared hosting, you generally don't control the PTR record; the hosting provider does. The PTR record will likely point to a generic hostname associated with the hosting provider's servers.

Expert from Email Geeks explains hostname patterns are relevant in three situations: human investigation/support requests (where 'mta-' indicates a mail server), "dynamically assigned ip address" blacklists (treating mta- differently from ec2-), and identifying the entity running the mail server.

Expert from Word to the Wise responds on ensuring your reverse DNS (PTR) record matches your forward DNS (A) record is critical. The server hostname should resolve correctly to the IP address sending email. This builds reputation and trust which are necessary for deliverability.

Expert from Email Geeks shares that the hostname chosen for a PTR record should clearly indicate it belongs to you and is a mail server, suggesting a consistent naming scheme for pool mail servers. Examples include <http://mail13.esp.com|mail13.esp.com> or <http://mail13.pool.esp.com|mail13.pool.esp.com> for esp.com.

Documentation from DigitalOcean explains how to configure PTR records for Droplets (virtual servers) and highlights its importance for email deliverability. It states that the hostname in the PTR record should match the hostname used in your email server's HELO/EHLO greeting and should be a valid, resolvable domain name. For shared IPs, this is managed by the provider.

Documentation from AWS explains about reverse DNS lookup which must match the forward DNS record (A record) of the hostname. This is a fundamental requirement for many email servers to accept messages. When using shared IPs, the ESP or cloud provider typically manages the PTR records.

Documentation from RFC 1912 explains general DNS operational and PTR record naming conventions. It suggests that PTR records should point to a fully qualified domain name (FQDN) and advises against using generic or ambiguous names. For shared IPs, it implies that the PTR should indicate ownership and responsibility.

Documentation from Google Workspace Admin Help explains that the PTR record must resolve to the same IP address as the corresponding A record, and the hostname in the PTR record should match the hostname used in the SMTP banner and HELO/EHLO greeting. This helps ensure proper reverse DNS lookup and email authentication.

Documentation from Microsoft Learn explains the importance of reverse DNS (PTR) records for outbound email. It states that a matching PTR record for the sending IP address is a crucial factor in establishing trust and avoiding spam filters. For shared IPs, the recommendation is to coordinate with the service provider to ensure proper PTR record configuration.