How to Prevent Spoofing: Stopping Scammers From Sending Emails in Your Company's Name
Have you ever had a customer call to ask if you really sent them an email — one you know nothing about? It's an unsettling moment, and it's happening to businesses more and more often. Email impersonation and domain spoofing have become one of the most common tools in a cybercriminal's playbook, and if you don't know how to prevent spoofing, your company's name could already be doing a scammer's dirty work without you knowing it.
The good news: spoofing is preventable. With the right combination of email authentication, account security, and staff awareness, you can make it far harder for criminals to hide behind your domain.
What Is Email Spoofing?
Email spoofing happens when a cybercriminal sends a message designed to look like it came from your company — think accounts@yourcompany.co.uk, support@yourcompany.co.uk, or info@yourcompany.co.uk. To the person receiving it, the email can look entirely genuine, right down to the branding and tone. Scammers use this trick to run invoice fraud, payment diversion scams, phishing attacks, credential theft, malware delivery, and full-blown Business Email Compromise (BEC).
Why It's More Than Just an IT Problem
When someone spoofs your domain, they're not just targeting whoever opens the email — they're targeting your reputation. Left unchecked, spoofing can chip away at customer trust, cause real financial losses through fraudulent payments, expose your organisation to wider cybersecurity risks, damage your brand, and even raise compliance and data protection concerns.
For many businesses, the first sign of trouble is a worried client forwarding a suspicious email and asking, "Did this really come from you?" By the time that question lands in your inbox, your domain may already be being abused — which is exactly why prevention has to come before the phone starts ringing.
How to Prevent Spoofing: 6 Proven Defences
1. Implement SPF Records
SPF (Sender Policy Framework) is usually the first line of defence. It lets you specify exactly which mail servers are authorised to send email on behalf of your domain, so when a message arrives, the recipient's server can check your SPF record and verify whether the sender is legitimate. Done properly, SPF cuts down on fraudulent emails, improves deliverability, and builds trust with email providers. If your business runs on Microsoft 365, getting SPF configured correctly should be a non-negotiable part of your email security setup.
2. Enable DKIM Authentication
DomainKeys Identified Mail (DKIM) adds a digital signature to every email you send — think of it as an electronic seal of authenticity. It allows receiving mail systems to confirm that a message genuinely came from your organisation and that its content hasn't been altered in transit. On its own, DKIM strengthens sender identity and message integrity; alongside SPF and DMARC, it forms a much harder authentication barrier for scammers to get past.
3. Deploy DMARC Protection
DMARC (Domain-based Message Authentication, Reporting and Conformance) ties SPF and DKIM together and tells receiving mail systems what to actually do when a message fails authentication. You can set it to:
- None – monitor suspicious activity without blocking anything
- Quarantine – send failed messages straight to junk
- Reject – block unauthorised emails outright
For any business that takes brand protection seriously, a properly configured DMARC policy is one of the most effective tools available.
4. Secure Your Microsoft 365 Environment
Spoofing attacks are frequently paired with attempts to compromise real accounts, so locking down Microsoft 365 matters just as much as authenticating outbound mail. That means enabling Multi-Factor Authentication (MFA), applying Conditional Access Policies and Security Defaults, and turning on anti-phishing, Safe Links, and Safe Attachments protection. At Dolphin IT Solutions, tightening up Microsoft 365 environments is consistently one of the highest-impact steps we take when helping businesses reduce cyber risk.
5. Monitor Your Domain for Abuse
Too many organisations set up their email security once and never look at it again. Regular monitoring — particularly through DMARC reporting — gives you ongoing visibility into spoofing attempts, misconfigured mail systems, authentication failures, and emerging threats, so you can catch problems before a customer does.
6. Train Your Employees
No amount of technology replaces a well-trained team. Staff should know how to spot suspicious requests, unexpected invoices, fake payment instructions, credential theft attempts, and malicious links or attachments. Regular security awareness training remains one of the simplest, most cost-effective ways to reduce the odds of a successful phishing attack.
Warning Signs Your Domain May Already Be Spoofed
A few red flags are worth watching for: customers reporting suspicious emails, suppliers querying payment requests they didn't expect, a rise in spam complaints, unusual email delivery issues, or DMARC reports showing failed authentication. If any of these show up, it's worth investigating straight away rather than waiting to see if it happens again.
How Dolphin IT Solutions Can Help
Preventing spoofing takes more than basic spam filtering. At Dolphin IT Solutions, we work with businesses to configure SPF, DKIM and DMARC correctly, secure their Microsoft 365 environment, roll out multi-factor authentication, and keep monitoring domains for suspicious activity long after the initial setup is done.
Email spoofing remains one of the most effective tools in a cybercriminal's arsenal — but it's also one of the most preventable, once SPF, DKIM, DMARC, Microsoft 365 security controls, and staff awareness training are all working together. Taking a proactive approach doesn't just protect your business from fraud; it protects the trust your customers place in your brand every time they open an email from you.
If you're not sure whether your domain is properly protected, get in touch with Dolphin IT Solutions for a security review and expert guidance.
