Question 1

What is SPF (Sender Policy Framework)?

Accepted Answer

SPF is an email authentication standard that specifies which mail servers are authorized to send email for your domain. SPF records are published as DNS TXT records and validated by receiving mail servers. Without SPF, anyone can forge emails claiming to be from your domain.

Question 2

What is DMARC (Domain-based Message Authentication)?

Accepted Answer

DMARC builds on SPF and DKIM to prevent email spoofing. It tells receiving mail servers what to do when authentication fails (reject, quarantine, or allow) and provides reporting on authentication results. DMARC is now required by Gmail and Yahoo for bulk senders.

Question 3

What is DKIM (DomainKeys Identified Mail)?

Accepted Answer

DKIM adds a cryptographic signature to outgoing emails, proving the message was not modified in transit. The signature is verified using a public key published in DNS. DKIM provides email integrity and non-repudiation.

Question 4

What is Why Emails Go to Spam?

Accepted Answer

Legitimate emails land in spam due to missing authentication (SPF, DKIM, DMARC), poor sender reputation, blacklisted servers, content triggers, or technical issues. Understanding the root cause requires checking DNS records, authentication alignment, and sender reputation.

Question 5

What is SPF, DKIM, and DMARC Together?

Accepted Answer

SPF defines who may send email. DKIM proves the message was not altered. DMARC tells receivers what to do if checks fail. All three are required for modern email authentication and prevent domain spoofing.

Question 6

What is Email Deliverability Testing?

Accepted Answer

Email deliverability testing validates DNS authentication (SPF, DKIM, DMARC), checks blacklist status, verifies MX records, and measures inbox placement rates. Automated testing through APIs enables continuous monitoring and prevents reputation degradation.

Question 7

What is Email Blacklists (RBLs)?

Accepted Answer

Email blacklists (RBLs - Real-time Blacklists) are databases of IP addresses and domains known for sending spam. Mail servers query RBLs before accepting email to filter malicious senders. Blacklisting causes immediate deliverability failure.

Question 8

What is How to Set Up SPF Records?

Accepted Answer

SPF setup requires creating a DNS TXT record at your root domain that lists authorized mail servers. The record uses mechanisms (ip4, ip6, include, a, mx) and a qualifier (~all or -all) to define which servers can send email on your behalf.

Question 9

What is DMARC Policy Configuration?

Accepted Answer

DMARC policy determines what happens when email authentication fails. The three policy levels are p=none (monitor only), p=quarantine (spam folder), and p=reject (block delivery). Policy should be implemented gradually using the pct= parameter.

Question 10

What is DNSSEC (DNS Security Extensions)?

Accepted Answer

DNSSEC is a set of security extensions for DNS that adds cryptographic authentication to DNS responses. It protects against DNS spoofing and cache poisoning by using digital signatures to validate DNS records. DNSSEC ensures DNS data is authentic and unmodified, but does not encrypt the data.

Question 11

What is BIMI (Brand Indicators for Message Identification)?

Accepted Answer

BIMI allows brands to display their logo next to authenticated emails in recipient inboxes. BIMI requires DMARC enforcement (p=quarantine or p=reject) and a verified mark certificate (VMC). Brand logos increase email trust and engagement.

Question 12

What is MTA-STS (Mail Transfer Agent Strict Transport Security)?

Accepted Answer

MTA-STS forces TLS encryption for email transmission between mail servers. It prevents downgrade attacks and man-in-the-middle interception by requiring encrypted connections through policy files published via HTTPS and DNS.

Question 13

What is DANE (DNS-based Authentication of Named Entities)?

Accepted Answer

DANE uses DNSSEC to publish TLS certificate fingerprints in DNS TLSA records, enabling certificate validation without relying on Certificate Authorities. For email, DANE prevents man-in-the-middle attacks by binding TLS certificates to DNS-verified identities.

IntoDNS.ai Reference & Citations

Email Authentication

BIMI (Brand Indicators for Message Identification)

DKIM (DomainKeys Identified Mail)

DMARC (Domain-based Message Authentication)

DMARC Policy Configuration

How to Set Up SPF Records

SPF (Sender Policy Framework)

SPF, DKIM, and DMARC Together

DNS Security

DNSSEC (DNS Security Extensions)

Transport Security

DANE (DNS-based Authentication of Named Entities)

MTA-STS (Mail Transfer Agent Strict Transport Security)

Deliverability

Email Blacklists (RBLs)

Email Deliverability Testing

Why Emails Go to Spam