Does using TLS matter for email deliverability or inbox placement?
Summary
What email marketers say11Marketer opinions
Email marketer from EmailGeeksForum.com says configuring TLS for your outgoing mail server is a must to secure your data and reduce the likelyhood of man-in-the-middle attacks. Using TLS helps maintain email security, which can positively influence deliverability.
Marketer from Email Geeks recommends using clear-text or TLSv1.2 and NOT pretending that v1/v1.1 are protecting your email in transit. They suggest to just go ahead and do `-TLSv1.1:-TLSv1.0:-SSLv3:-SSLv2` and drop back to plain-text if an attempt to negotiate opportunistic TLS via `STARTTLS` fails due to the remote not supporting `+TLSv1.2:+TLSv1.3`.
Email marketer from StackOverflow shares that setting up TLS is really important to secure your email, without it anyone on your network may be able to see your password and email data. Using TLS helps maintain email security, which can positively influence deliverability.
Email marketer from SMTP2GO highlights that TLS encrypts email communications to protect data during transit. Using TLS helps maintain email security, which can positively influence deliverability by signaling to mailbox providers that the sender is committed to secure practices.
Marketer from Email Geeks shares that you should disable TLSv1 and v1.1. If you can't make TLSv1.2 work, you should not pretend.
Email marketer from Sendinblue emphasizes the importance of TLS encryption for secure email deliverability. It ensures the privacy and security of email communications during transmission, preventing unauthorized access. It may improve deliverability by meeting security standards expected by mailbox providers.
Email marketer from Reddit explains that while TLS encrypts email content during transit, preventing eavesdropping, it doesn't directly influence deliverability metrics like inbox placement. However, some ISPs may view TLS usage as a positive signal, subtly improving reputation.
Marketer from Email Geeks shares that it's absurd to question using TLS, as it requires basically zero effort for Opportunistic TLS. Not using TLS outbound looks bad and someone out there might use the data as a signal. Something like 85-90% of the world's email arrives to Gmail via TLS so you don't want to be an outlier.
Email marketer from PrivacyMatters.com explains that configuring TLS for your outgoing mail server is a must to secure your data and reduce the likelyhood of man-in-the-middle attacks. Using TLS helps maintain email security, which can positively influence deliverability.
Email marketer from SparkPost states that while TLS is essential for securing email transmission and protecting data, the lack of TLS doesn't necessarily affect the deliverability. However, they also mention that its absence might negatively affect the sending reputation of an email sender.
Email marketer from Mailjet explains that TLS encrypts the connection between mail servers to protect the contents of emails during transmission. It prevents eavesdropping and tampering. While it primarily addresses security, some email providers may consider it a factor in reputation and deliverability.
What the experts say8Expert opinions
Expert from Email Geeks says Google has been strongly in favor of TLS for web traffic and will derank you if you’re not using good TLS. They may do something similar with email in the future.
Expert from Word to the Wise shares that one of the benefits of SMTP TLS Reporting is that it helps catch MITM attacks. If the TLS is broken, the receiving server may be able to tell you that something is wrong, which could help with deliverability.
Expert from Email Geeks mentions that if there’s a choice between TLS 1.1 and clear text, you need to decide which you prefer, if you’re sending to a server that doesn’t speak 1.2 and your client is configured to refuse 1.1 that’s where you are.
Expert from Email Geeks explains that you have three choices when interoperating with an SMTP peer that doesn’t support TLS 1.2: use a transport with TLS 1.1 or below, refuse to transfer the mail, or send the mail plain text over an unencrypted transport.
Expert from Email Geeks shares that there's no real deliverability benefit to TLS, other than avoiding the red locks and encryption warnings.
Expert from Email Geeks explains that TLS isn’t really a deliverability issue, unless you’re sending over IPv6, in which case you should use TLS.
Expert from Email Geeks points out that US government policy is for STARTTLS and there isn’t any requirement for which TLS version to use. They’re very clear that 1.2 or 1.3 is required for government websites, but they just want something for email. Recommending to review Binding Operational Directive: <https://www.cisa.gov/news-events/directives/binding-operational-directive-18-01>
Expert from SpamResource shares that the encryption of your email communication is important but not essential to reaching the inbox. It does not affect deliverability as long as the SPF, DKIM and DMARC records are appropriately configured.
What the documentation says3Technical articles
Documentation from RFC details how a SMTP connection can be secured with Transport Layer Security (TLS) to provide confidentiality and integrity protection. Although its implementation is very import for protecting data across networks it does not guarantee delivery of messages.
Documentation from NIST provides guidance for configuring TLS (Transport Layer Security) server software. This documentation focuses on protocols, key exchange, and digital signatures, with the primary goal of securing communication and protecting data confidentiality and integrity. Although this will help protect data across networks it does not guarantee delivery of messages.
Documentation from Microsoft Learn details that Exchange Online requires TLS 1.2 for connections. While not directly stated as impacting deliverability, failure to meet this requirement will prevent mail flow. Therefore, it indirectly impacts deliverability by ensuring messages can be transmitted in the first place.