Email is central to business communication, but it’s also one of the easiest ways for cybercriminals to attack. Spoofing and phishing are on the rise, with attackers impersonating trusted senders to steal data, damage reputations, and compromise customer trust.
That is why a well-configured Sender Policy Framework (SPF) policy is important. SPF helps your company take control by authorizing which servers can send emails on behalf of its domain, reducing the risk of abuse and improving deliverability.
At Sendmarc, we make SPF easy. We help businesses configure, monitor, and manage their SPF policies with precision so their emails stay secure, authenticated, and trusted from inbox to inbox.
SPF policy benefits:
An SPF policy is a set of rules published in your organization’s DNS record. It tells receiving email servers which IP addresses or sending services are authorized to send emails on behalf of a domain. This policy is implemented through an SPF record – a specially formatted DNS TXT record.
By publishing an SPF policy, your company is protecting its reputation and preventing cybercriminals from impersonating its brand in phishing or spoofing campaigns.
SPF is an email authentication protocol created to combat spoofing. Spoofing is when threat actors send emails that seem to come from your business’s domain, aiming to trick recipients into engaging with malicious content.
An SPF policy helps stop this by letting domain owners specify which servers are permitted to send emails using their domain name. Specifically, it lists the IP addresses of these servers. These are published in the DNS as part of the SPF record.
When an email arrives claiming to be from your organization’s domain, the recipient’s email server compares the IP of the sending server against the SPF record. If the IP of the sending server is listed, the email passes SPF authentication. If not, the message might be marked as Spam, flagged as suspicious, or blocked altogether.
The SPF record lives in the DNS zone as a TXT record and outlines which servers are allowed to send messages on your business’s behalf. It uses mechanisms such as:
a y mx: Authorizes the domain’s A or AAAA and MX recordsip4 y ip6: Specifies exact IP addresses or ranges that are allowed to send emailinclude: Refers to the SPF records of the target address and is widely used by third-party services (for example, email platforms or marketing tools your organization uses)all: Defines what to do with email that doesn’t match any mechanisms – used with the qualifiers:+all (pass)-all (fail)~all (softfail)?all (neutral)A well-written SPF record should include all legitimate sending sources while avoiding misconfigurations and the DNS lookup limit (10 lookups).
One of the most important benefits of an SPF policy is its ability to stop unauthorized use of your company’s domain. Cybercriminals often impersonate trusted brands to trick users into clicking malicious links or revealing sensitive data. By implementing an SPF policy, your business clearly defines which senders are legitimate, making it significantly harder for attackers to impersonate its domain.
Your organization’s email domain is part of its brand. If it’s used in phishing campaigns, it can be blacklisted by major providers – damaging your company’s reputation and decreasing customer trust. SPF helps by reducing the chance of your business’s domain being used by malicious actors.
When your organization’s SPF policy is properly configured, receiving email servers are more likely to trust its emails. This reduces the risk of legitimate emails being flagged as Spam or rejected, boosting the delivery of marketing campaigns, transactional emails, and business communications.
SPF is a globally recognized email authentication standard and a key component of many compliance frameworks. Used alongside Domain-based Message Authentication, Reporting, and Conformance (DMARC) and DomainKeys Identified Mail (DKIM), SPF strengthens your company’s email security posture and helps it meet industry best practices and regulatory requirements.
See how your business can benefit from a correctly configured SPF policy.
An SPF policy defines all legitimate email servers authorized to send messages on your organization’s behalf. This includes:
Accurately listing these senders ensures that your company’s messages pass SPF checks and are trusted by recipient systems.
An SPF policy is implemented through a DNS TXT record, meaning your business can manage and update it without making changes to its actual email infrastructure. This DNS-level control makes the SPF policy flexible and adaptable as your organization’s email setup evolves.
SPF works best as part of a layered email authentication strategy. When combined with DKIM (which verifies message integrity) and DMARC (which enforces your company’s policy for non-authenticated emails and provides visibility), SPF helps:
Your business can define how recipient servers should handle emails that fail SPF checks:
+all): Accept unauthorized messages-all): Reject unauthorized messages outright~all): Accept them but flag them as suspicious?all): Take no specific actionOf the above, only fail and softfail are recommended.
SPF doesn’t include reporting. But, when integrated with DMARC, your organization gains access to detailed reports showing:
The visibility from DMARC helps your business fine-tune its policy and respond quickly to threats.
An SPF policy works by publishing a DNS TXT record that lists authorized sending servers for your business’s domain. When an email is received, the recipient’s email server checks this SPF record to verify if the sending server is listed. Emails sent from unauthorized servers can be flagged or rejected, helping protect your organization’s domain from misuse and reducing fraudulent emails.
While SPF records function independently, managing and monitoring them manually can be complex, especially as your business’s email environment grows. Without proper tools, it’s difficult to track SPF failures, DNS lookup limits, and unauthorized senders. Automated SPF management and monitoring platforms simplify this process, providing actionable insights and ensuring your organization’s SPF policy remains effective.
Sendmarc helps your company configure and manage SPF, DMARC, and DKIM so your business stays protected, compliant, and trusted.
