What causes SPF authentication dips in Google Postmaster Tools graphs?
Summary
What email marketers say12Marketer opinions
Email marketer from Email Geeks explains that the Google Postmaster Tools authentication dashboard considers alignment, like DMARC, and that dips to 0% on SPF may be due to domain spoofing or unauthenticated sends. Insufficient send volume might also prevent data points from displaying, holding the line at its previous value.
Email marketer from Reddit explains that if using a CRM, SPF should be configured to include the CRM's sending servers. Dips in SPF authentication could mean the CRM's IP addresses aren't consistently included in the SPF record, or the CRM is using different IPs.
Email marketer from EasyDMARC Blog explains that exceeding the SPF DNS lookup limit can be resolved by 'flattening' the SPF record. Flattening involves replacing 'include:' mechanisms with the actual IP addresses, which can prevent authentication dips.
Email marketer from Mailgun Blog explains that SPF failures can occur due to various reasons, including exceeding the 10 DNS lookup limit, incorrect SPF record syntax, or the sending server not being authorized in the SPF record.
Email marketer from EmailGeekForum explains that using third-party email services or CDPs without proper SPF configuration can lead to dips in authentication rates. Ensure all sending sources are authorized.
Email marketer from SparkPost Blog explains that IP address reputation can impact SPF authentication results. If sending IPs are new or have a poor reputation, SPF checks may be less reliable, causing dips.
Email marketer from Litmus Blog shares that monitoring SPF records for changes or errors is crucial. Dips in SPF authentication can result from unintended modifications to the SPF record, like typos or incorrect IP addresses.
Email marketer from Postmark Blog shares that on shared IPs, the sending behavior of other users can affect your SPF results. If other users on the shared IP are sending spam, it might impact your SPF authentication rates.
Email marketer from Email Geeks explains that Google Postmaster Tools reports the SPF success rate for the authenticated domain. It is possible for an email to have a 100% DKIM and DMARC pass rate but a 0% SPF pass rate if the CRM DKIM signs with a domain different from the SPF domain.
Email marketer from AuthSMTP Knowledge Base shares common mistakes in SPF records, such as using multiple 'include:' mechanisms that lead to exceeding DNS lookup limits or not including all necessary sending IPs. Correcting these mistakes can stabilize SPF results.
Email marketer from StackOverflow explains that SPF 'permerror' (permanent error) issues, such as exceeding the 10 DNS lookup limit, can cause authentication failures. These errors may lead to sudden dips in Postmaster Tools' SPF graphs.
Email marketer from ReturnPath Blog (via Wayback Machine) explains that temporary DNS resolution issues can cause SPF checks to fail intermittently. These failures can lead to short-term dips in SPF authentication rates reported by Google.
What the experts say2Expert opinions
Expert from Spam Resource explains that SPF authentication dips directly impact email deliverability. These dips often are a result of misconfiguration of records and the negative reputation of shared IPs. Temporary and sustained Authentication errors will always have a negative impact on your sender reputation.
Expert from Word to the Wise explains that SPF failures, leading to dips in Postmaster Tools graphs, often occur when using third-party senders or ESPs. If the SPF record does not include the sending source's IP addresses or domain via 'include:', authentication will fail.
What the documentation says4Technical articles
Documentation from Microsoft Learn explains that SPF failures can be either hard fails or soft fails. A hard fail indicates the email should be rejected, while a soft fail suggests the email is suspicious. Google Postmaster Tools may treat these differently, leading to dips.
Documentation from RFC 7208 (the SPF standard) explains that syntax errors in the SPF record can cause authentication failures. Even minor typos can invalidate the entire SPF record, resulting in authentication dips.
Documentation from Google Workspace Admin Help explains that Google Postmaster Tools displays SPF authentication rates based on the percentage of emails that pass SPF checks. Dips can indicate issues with SPF configuration or unauthorized sending sources.
Documentation from DMARC.org explains that SPF failures, even with a DMARC policy in place, can still impact reputation. Google Postmaster Tools reflects SPF results, separate from DMARC alignment. SPF failing might indicate configuration issues even if DMARC is passing due to DKIM.