How does rDNS impact email deliverability when using dedicated IPs?
Summary
What email marketers say11Marketer opinions
Email marketer from Mailjet explains that rDNS helps to establish trust with ISPs and improve deliverability. It confirms that the IP address is associated with a legitimate domain, which makes it less likely for emails to be marked as spam. Setting up rDNS is a best practice for dedicated IPs.
Email marketer from Super User explains that if you send email from a server with no reverse DNS record, many mail servers will classify the email as spam. Creating a reverse DNS record for your mail server's IP address will drastically increase your deliverability.
Email marketer from Email Geeks shares that some mail receivers do treat dynamic rDNS records with suspicion, but a competent ESP should have a record that doesn't appear dynamic.
Email marketer from Easyspace explains that reverse DNS (rDNS) helps in email delivery by verifying the identity of the server sending the email. It also helps in reducing spam and helps your email get delivered and reach your target customer.
Email marketer from StackOverflow shares that many email servers will reject connections from servers without reverse DNS. Set it or suffer.
Email marketer from Email Geeks believes that the issue could only happen if the domain used in the rDNS is having a bad reputation already.
Email marketer from Reddit explains that having a properly configured rDNS record is like having a verified identity for your email server. It tells receiving servers that you are who you say you are, which can significantly improve your chances of landing in the inbox rather than the spam folder. If you're using dedicated IPs, setting up rDNS is a must.
Email marketer from DigitalOcean explains that reverse DNS (rDNS) is the resolution of an IP address to a domain name, the opposite to forward DNS resolution. rDNS is commonly used to verify the legitimacy of a server's IP address, typically for email servers. Many email service providers will reject emails that come from IP addresses without rDNS configured, or whose rDNS entries don't match the sending domain.
Email marketer from SendGrid responds that rDNS is an important factor in email deliverability because it provides a way for receiving mail servers to verify the identity of the sending server. Without a valid rDNS record, emails are more likely to be flagged as spam or rejected outright. Setting up a reverse DNS record for your sending IP address helps to build trust with receiving mail servers and improve your deliverability rates.
Email marketer from SparkPost shares that a properly configured rDNS record is essential for maintaining a positive sender reputation. It helps to verify the identity of the sending server and can prevent emails from being blocked or filtered as spam. They recommend that all senders using dedicated IPs should configure rDNS.
Email marketer from Namecheap explains that setting up a reverse DNS record for your server IP can help prevent your emails from being flagged as spam. Reverse DNS ensures that the connection attempts by the server are genuine, which is the key point in gaining trust and raising the reputation of the IP address. With reverse DNS configured, more mail servers will positively treat your messages and allow them to get to the recipient's inbox.
What the experts say4Expert opinions
Expert from Word to the Wise emphasizes that a PTR record must exist and be associated with the IP address for your mail server to be considered legitimate by many receivers. This is a basic requirement for good deliverability, especially when using dedicated IPs.
Expert from Email Geeks shares that the main reason to do client-specific, white label reverse DNS is for clients who want no trace of any brand other than theirs in the email headers, rather than anything technical. If the reverse DNS points to hostnames in the client's domain, the ESP relies on the client to do any needed updates.
Expert from Spam Resource states that having a correct rDNS is important, but it is not sufficient to get your mail delivered. He elaborates that not having a correct rDNS can definitely cause delivery problems.
Expert from Email Geeks explains that it's probably fine for ESPs to use their own rDNS even for dedicated IPs, as long as the IP -> domain name -> IP works. One of her clients has dedicated IPs and half have rDNS pointing to their domain and half rDNS pointing to the ESP.
What the documentation says5Technical articles
Documentation from Exa Infrastructure shares that rDNS allows a mail server to verify that a sender is who they claim to be. This is done by performing a reverse DNS lookup on the IP address of the sending mail server and comparing the hostname returned to the domain name used in the email's "From" address. If the two match, it increases the likelihood that the email is legitimate.
Documentation from Google Workspace Admin Help explains that a matching PTR record (reverse DNS) is required for the sending IP address. The PTR record must match the hostname specified in the HELO or EHLO greeting. If there's no matching PTR record, or if the hostname in the PTR record doesn't match the sending hostname, the message might get marked as spam.
Documentation from RFC Editor recommends that every internet-reachable host should have a reverse address record (PTR) in the in-addr.arpa domain. Failing to configure accurate PTR records can lead to email being rejected by some mail servers.
Documentation from Microsoft Learn indicates that reverse DNS lookup is a common anti-spam technique. Many mail servers perform reverse DNS lookups to verify the hostname associated with the sending IP address. If no PTR record is found, or if it doesn't match the forward DNS record, the email might be considered suspicious.
Documentation from Hetzner details that rDNS records are an important criteria for reverse DNS lookups. This is done to guarantee the authenticity of an email server. If no rDNS record exists for an IP address, many mail servers automatically categorize emails as spam.