Why is Senderscore showing a subdomain I don't recognize?

Key findings

• Return-path domain: The unfamiliar subdomain (e.g., bounce.yourcompany.com) is most likely your email's return-path domain (also known as the MailFrom or Envelope From address), which is distinct from the 'From:' address you see in your inbox.
• Technical function: This domain handles bounces and other mail stream communications and is crucial for SPF authentication. It's often managed by your ESP (like Salesforce Marketing Cloud, SFMC) and may not be explicitly listed in your sender profiles.
• SenderScore visibility: SenderScore, a tool for monitoring email sender reputation, tracks the domain associated with the IP address sending the mail, which includes the return-path domain.
• Domain alignment: While the return-path subdomain may differ from your marketing subdomain, it typically aligns with your root organizational domain. This alignment is vital for DMARC authentication and overall deliverability.
• Expected behavior: It is standard practice for ESPs to use a separate return-path or bounce domain, and this is generally not an issue if your emails are properly authenticating and reaching the inbox.

Key considerations

• Check email headers: To confirm the return-path domain, view the original source code of one of your sent emails (e.g., in Gmail, select 'Show original'). The return-path will be listed in the headers. Mailjet provides a comprehensive guide on sender score and email reputation which includes how to interpret these.
• Do not match domains: It is generally not advisable to force the return-path domain to match your 'From:' domain, as this can break critical email functionalities, including bounce processing and authentication.
• Verify authentication: Ensure that your SPF and DKIM records are correctly set up for all subdomains being used by your ESP to send mail, even the return-path one. This ensures proper authentication.
• Consult your ESP: If you have concerns about an unexpected subdomain or its setup, contact your ESP's support. They can provide specific details on how your email streams are configured and authenticated.
• Focus on deliverability: If your emails are consistently reaching the inbox and you are not experiencing significant bounce rates or blocklistings, the SenderScore subdomain discrepancy is likely benign. Prioritize actual inbox placement over a single metric, especially if it's a vanity score.

Key opinions

• Unexpected discovery: Marketers are often surprised to find subdomains they don't explicitly control or recognize listed by sender reputation services, especially when they differ from their main sending domains.
• Authentication questions: There's common confusion about whether these unfamiliar subdomains indicate a problem with authentication setup, particularly when their ESP is responsible for configuration.
• Desire for control: Some marketers express a desire for all sending domains to match for simplicity or perceived control, even if it's not technically necessary or advisable.
• Deliverability impact: The primary concern stems from worries that an unrecognized subdomain could negatively affect deliverability rates or lead to emails being marked as spam.
• List hygiene importance: Many marketers realize that poor list hygiene and sending to unengaged contacts are more significant factors impacting deliverability than minor subdomain discrepancies.

Key considerations

• ESPs manage subdomains: Recognize that ESPs often manage multiple subdomains for different functions (e.g., sending, bounces, links), and these may not always be visible or configurable within standard user interfaces. MailMonitor offers essential fixes for low sender scores, many of which depend on understanding ESP setups.
• Verify with support: If unsure, marketers should submit support tickets to their ESP to understand the purpose and configuration of any unexpected subdomains associated with their sending.
• Prioritize inbox placement: Instead of obsessing over a single metric like SenderScore, marketers should focus on tangible deliverability metrics: open rates, click-through rates, and actual inbox placement, which are more indicative of success.
• Review list quality: Aggressively cleaning email lists and targeting engaged subscribers will likely have a far greater positive impact on deliverability than troubleshooting a technically correct, but unfamiliar, return-path domain.
• Understand domain roles: It's beneficial for marketers to grasp the distinction between the visible 'From' domain and the hidden 'return-path' domain to demystify how email systems function.

Key opinions

• Return-path explanation: The unfamiliar subdomain is almost certainly the return-path domain, used for bounce handling and SPF authentication.
• Two 'from' addresses: Emails have two primary 'from' addresses: the 5321.from (return-path, authenticated by SPF, often hidden) and the 5322.from (the visible 'From:' address).
• Don't match domains: It is strongly advised not to try and make the return-path domain match the visible 'From:' domain, as this can cause significant issues with mail processing.
• SenderScore's role: SenderScore is primarily a 'vanity score' that doesn't directly influence deliverability for many mail streams, especially if emails are already delivering successfully. Laura Atkins, an expert at Word to the Wise, further elaborates on domains and reputation.
• Proofpoint vs. SenderScore: Proofpoint (a security vendor) does not feed data into SenderScore. Deliverability issues flagged by Proofpoint are typically unrelated to SenderScore metrics.

Key considerations

• Confirm headers: Always verify the return-path domain by examining the email headers. This is the most reliable way to understand what SenderScore is detecting.
• Consult your ESP: If questions persist, engage your ESP's deliverability team for specific advice, especially concerning any non-existent intended sending subdomains.
• Focus on root causes: If delivery is suffering, focus on core issues like sending to unengaged recipients or poor list quality, which receiver filters often interpret negatively, rather than minor subdomain visibility issues.
• Avoid unauthorized changes: Do not make changes to domain configurations without explicit approval and guidance from your ESP, as this can severely disrupt email authentication and delivery.
• Leverage postmaster tools: For specific insights into deliverability issues with providers like Proofpoint, reaching out to their postmaster support (e.g., postmaster@proofpoint.com) may provide more actionable intelligence than SenderScore.

Key findings

• Subdomain purpose: Subdomains are frequently used to segment email traffic (e.g., marketing, transactional, bounce handling) to protect the primary domain's reputation.
• Authentication configuration: Proper SPF, DKIM, and DMARC records must be configured for each sending subdomain to ensure email authentication passes. ActiveCampaign provides insights on subdomains and deliverability.
• Reputation isolation: Subdomains allow for separate reputation tracking, meaning issues with one email stream (e.g., bounces) do not necessarily impact the reputation of another (e.g., marketing).
• Dedicated IPs: Setting up dedicated IPs for email sending often involves associating them with specific subdomains for signing emails.
• DMARC policy impact: Strict DMARC policies can affect which subdomains can be used, sometimes requiring specific configurations or workarounds from the ESP.

Key considerations

• DNS configuration: Ensure that all necessary DNS records (A, CNAME, MX, TXT for SPF/DKIM) are correctly configured for any subdomains used by your ESP, including return-path domains.
• Monitoring subdomains: It is good practice to add and monitor individual subdomains in tools like Google Postmaster Tools to gain insights into their specific reputation metrics.
• ESPs' role: Understand that your ESP manages the underlying infrastructure and configurations for subdomains, even if they aren't directly exposed in your user interface.
• Alignment importance: While subdomains differentiate, DMARC requires alignment of the 5321.from (return-path) and 5322.from (visible 'From') domains with the organizational domain for proper authentication.