Email (electronic mail) has been a cornerstone of digital communication since the early days of the Internet. The first true email systems appeared in the early 1970s when Ray Tomlinson introduced the use of the @ symbol to designate email addresses on ARPANET. By the 1980s, email had become a critical tool within government agencies, universities, and eventually corporations. And yet, many businesses still don’t have a good grasp on the technology beyond emails and how to configure them to get the most out of it based on their business needs. This guide will provide all the information you need to understand emails, their security settings, and how to choose your email provider accordingly.
From technical novelty to business necessity
In the 1990s, as the internet became commercialized, email moved from research labs to the business world. Providers like Lotus Notes, Microsoft Exchange, and Novell GroupWise offered integrated messaging platforms for enterprise environments. Email was no longer a novelty—it became the default medium for business correspondence, documentation, and collaboration.
By the early 2000s, the rise of web-based email (Hotmail, Yahoo Mail, Gmail) and cloud-based groupware (Microsoft 365, Google Workspace) made email services accessible without dedicated infrastructure. This transition also introduced new challenges: spam, phishing, and data breaches.
Why email security matters today
In today’s cyber threat landscape, email is still the #1 attack vector for business compromises, including:
Phishing and spear phishing
Business Email Compromise (BEC)
Data exfiltration
Ransomware delivery
Because email systems carry sensitive personal, financial, and operational data, businesses must go beyond basic functionality and prioritize security, compliance, and resilience.
The basics: how does email work?
If you have ever had to configure an email address manually (for example, with a custom domain), you might have seen your provider’s settings for POP, IMAP, and SMTP. These are the basic protocols used for sending and receiving emails, but they’re not the only ones.
- An email protocol is a set of rules and standards that govern how email messages are sent, received, and stored between different email clients and servers. These protocols ensure that email communication is standardized and can be exchanged reliably, regardless of the specific software or hardware being used.
Receiving emails: POP3, IMAP, and Exchange
The protocols governing email reception are POP3, IMAP, and Exchange (or ActiveSync).
IMAP (Internet Message Access Protocol)
Emails are stored on the server and synced across multiple clients.
- Good for multi-device access
- Server-side organization
- Requires constant Internet
- More bandwidth usage
Exchange (ActiveSync)
Microsoft protocol offering real-time sync for emails, calendars, and contacts.
- Full-feature groupware
- Push notifications
- Excellent sync
- Vendor lock-in (Microsoft)
- Higher costs
Recommendations:
- Use IMAP if you need your email on multiple devices and you always want these emails to be synced.
- Use POP3 if you have offline requirements or if you want to differentiate what emails you want to see on different devices. It's always best to keep a backup of the emails on the server.
- Use Exchange if you are alreadcy operating in the Microsoft eco-system and you need additional features such as notification, reminders, calendar and contact synchronization.
Sending emails: SMTP
SMTP (Simple Email Transfer Protocol) is the protocol used for sending emails. It handles the transmission of messages from the sender’s email client to the recipient’s mail server.
SMTP is the most used protocol for sending emails. While there are other methods available (such as sending emails through APIs), SMTP is often the only option offered by email providers.
Key security features to look for
When choosing an email provider, prefer one that offers the following security features for your email service:
Encryption (in transit and at rest)
- TLS (STARTTLS) ensures that the provider enforces encryption in transit.
- S/MIME or PGP are used for end-to-end encryption. They verify that your email supports user-certificate based encryption.
- At-rest encryption checks if the provider encrypts stored messages and attachments (e.g., AES-256 encryption on disk).
Authentication and anti-spoofing
- SPF (Sender Policy Framework) specifies allowed senders for your domain. If SPF is active, your configuration will contain an entry like this: "v=spf1 include:spf.protection.outlook.com -all".
- DKIM (Domain Keys Identified Mail) digitally signs messages to prove their authenticity. It adds a public key to your DNS TXT records.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance) is a policy that specifies how to handle failed SPF and DKIM messages and generates reports on them. If your email supports DMARC, you will see an entry like this in your configuration: "mailto:dmarc@example.com".
- Choose a provider that allows you to enable and enforce Multi-Factor Authentication for all email accounts.
How to choose a secure email provider?
Besides the security features specified above, an email provider that values security will also offer the following:
- Offer data residency in your country or region (especially for PIPEDA/GDPR compliance).
- Comply with SOC2, ISO 27001, or similar certifications.
- Features like email archiving, legal hold, anti-malware scanning, and spam filtering.
- Zero-access encryption (E2EE).
Popular providers that offer such security features are Proton Mail, Zoho Mail, Google Workspace, and Microsoft 365.
Secure Configuration and hardening tips
Even with all these features enabled, a secure email service needs to be properly configured. Ensure that you trake the following steps when you set up your emails:
- Enforce TLS anywhere: ensure that SMTP servers require STARTTLS; disable legacy protocols like SMTP AUTH without TLS, POP3 without TLS, and older SSL versions.
- Set up user security policies: enforce strong password policies (min 12 chars, complexity rules); configure automatic session timeouts; conduct regular user training against phishing and social engineering.
- Enable audit logging and alerting: enable detailed email logs and login tracking; configure alerts for suspicious activities (e.g., logins from new locations or devices).
- If you use MDM (Mobile Device Management), enforce encryption and remote wipe for mobile devices; limit access from unauthorized mobile platforms.
Additional security measures
For advanced email security protection, consider using an email Gateway with Advanced Threat Protection. Services like Proofpoint, Mimecast, or Barracuda add a layer before mail reaches your inbox.
Enable archiving and eDiscovery. Long-term archiving ensures compliance with different security frameworks such as SEC, FINRA, and PIPEDA. EDiscovery tools will help you conduct legal investigations or audits.
Make sure that you also have a backup policy. Ensure mailboxes are backed up independently (cloud-to-cloud or local) with tools like SpinBackup, Dropsuite, or Acronis.
A final checklist before going live
Before you go live with your business email, double-check the following:
- SPF, DKIM, DMARC are configured and tested
- TLS is enforced for all inbound/outbound email
- MFA is enabled for all accounts
- Admin privileges are restricted and logged
- End-to-end encryption is either available or configured where needed
- Phishing simulations and training are in place
- Phishing simulations and training are in place
- Compliance documentation is stored and reviewed.
With these steps, you will run a secure and reliable email service for your business and your email users.