How to manage subdomain reputation when using multiple IP addresses for email sending?
Summary
What email marketers say8Marketer opinions
Email marketer from Validity suggests setting up feedback loops (FBLs) with major mailbox providers for each IP address to monitor complaint rates and identify potential reputation issues quickly.
Email marketer from SuperOffice suggests that A/B test different elements of your email campaign, such as subject lines, content, and sending times, to optimize your emails for better deliverability and engagement.
Email marketer from StackOverflow suggests implementing a DMARC policy that allows multiple senders by ensuring that both SPF and DKIM are properly configured and aligned for all sending IPs and subdomains.
Email marketer from Litmus shares that it's important to maintain consistent sending practices across all subdomains and IPs, including consistent volume, content, and authentication, to avoid triggering spam filters.
Email marketer from Mailjet shares that when using a subdomain on a new IP address, it is important to gradually warm up the IP address by slowly increasing sending volume. This allows mailbox providers to learn that the IP is sending legitimate mail.
Email marketer from EmailVendorSelection recommends properly delegating subdomains to each sending platform if using multiple platforms for email sending, ensuring each has its own separate configuration and reputation.
Email marketer from Reddit shares that it’s useful to separate different email streams (transactional vs. marketing) on different subdomains and IP addresses to isolate reputation issues.
Email marketer from GlockApps recommends monitoring the reputation of both your IP addresses and subdomains when using multiple IPs. They suggest using tools to track deliverability and sender score to identify any issues early.
What the experts say5Expert opinions
Expert from Word to the Wise explains that IP address and domain reputation are related, but distinct. You can have a good domain reputation and a bad IP reputation, or vice versa. When using multiple IPs, it's important to monitor the reputation of each one individually.
Expert from Email Geeks shares advice based on experience with Salesforce Marketing Cloud, including: 1. Inbound mail can only be received in one place. 2. Hostname DNS entries must be unique for each platform. 3. The best approach is to set up a new subdomain on the new platform and map the from address on top of it.
Expert from Email Geeks shares that SPF domains should be different for each setup, but the same d= domain can be used with different selectors for each sending setup. Also emphasizes the need to warm up the subdomains on the new IP addresses and infrastructure gradually.
Expert from Email Geeks explains that if the subdomains are used for sender addresses, aligned authentication with SPF and DKIM can be done from both providers simultaneously. He recommends gradually ramping up the volume from the new provider.
Expert from Word to the Wise emphasizes that proper authentication (SPF, DKIM, DMARC) is crucial when sending from multiple IP addresses or subdomains to maintain a consistent sender identity and avoid deliverability issues.
What the documentation says5Technical articles
Documentation from RFC Editor (RFC 6376) details how DKIM can be used to authenticate email from multiple sending infrastructures. It suggests using different DKIM selectors for each infrastructure to distinguish between them, while still using the same domain.
Documentation from Microsoft explains that maintaining a good sender reputation is critical to deliverability. Monitoring your reputation via Microsoft's SNDS program (if sending to Outlook.com or Hotmail users) can help you identify if your multiple IPs or subdomains are causing issues.
Documentation from Google Postmaster Tools explains that you can monitor your subdomain's reputation with Google by using their tools. This helps you understand how Google perceives your sending practices and identify any deliverability issues.
Documentation from SparkPost explains that to send email from multiple IP addresses using the same subdomain, you need to include all sending IPs in your SPF record. The SPF record should be updated to include each IP address or IP range.
Documentation from Amazon Web Services explains that using a dedicated IP allows you to build your own reputation. This documentation details how to authenticate your domain and setup the sending infrastructure in their environment.