Why mail goes to spam
Receiver checks, the records published by Beskos, and the remaining factors.
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Deliverability problems generally originate in one of four areas, three of which are DNS records. This article describes the checks a receiving server applies, in order.
The four checks
A receiving server evaluates the following before classifying a message.
- Whether SPF authorises the sending server. A failure indicates a forged sender.
- Whether the DKIM signature is valid. A failure indicates modification in transit.
- Whether DMARC specifies an action on failure, and whether that policy is enforced or monitoring only.
- Whether the sending address appears on a blocklist. On shared infrastructure, a single sender is sufficient to cause listing.
Records published by Beskos
SPF, DKIM and DMARC are generated for the domain at registration with a strict policy: SPF terminates in -all and DMARC is published as p=reject.
Outbound mail is transmitted through a relay on which each organisation has dedicated address space. Sending activity by another customer does not affect the organisation's reputation.
Factors outside configuration
Configuration does not determine inbox placement on its own. Delivery also depends on sending history, message content and the classification applied by each receiver, none of which is externally observable. Tools that claim to predict placement produce estimates.
The most common configuration error is exceeding the SPF lookup limit. The standard permits ten DNS lookups; each additional sending service consumes one. Beyond the limit, receivers disregard the SPF record entirely, with no visible error in the DNS zone.
Checking a domain
The mail check reads the public records of a domain and reports the result obtained by a receiving server, including the lookup count. No account or e-mail address is required.