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6 Best Practices for Securing a Corporate Email Gateway

Updated: Jan 4, 2023

An email gateway is an intermediary device that sits between an organisation’s local email server and the internet. It performs multiple functions by inspecting, filtering, and routing messages through rules based on specific conditions set by administrators. It provides a point of security control and inspection for outbound emails to help prevent spam, viruses, phishing attempts, or other threats from being transmitted via your organisation’s email system.

An organisation typically has an existing mail server solution, whether on-premises or cloud-based. An email gateway should not replace this existing solution. Instead, it should be implemented as a secondary layer of security. This blog post outlines 6 best practices to consider when implementing an email gateway solution.

1. Understaffed or overwhelmed by email security?

If your organisation is experiencing an increasing number of malicious emails being sent through its email infrastructure, or if you’re struggling to keep up with the sheer volume of emails being sent and received by your users every day, partnering with a platform that offers email security solutions in Singapore may be the best course of action.

An email gateway provides additional security measures that can help mitigate or prevent the spread of spam and phishing attempts through your organisation’s email system. A gateway can also monitor outgoing emails for regulatory compliance purposes, such as ensuring that no restricted data elements, such as credit card numbers, are contained in your emails.

An email gateway can also help provide a more consistent experience for your users, as it can be configured to block certain types of emails, such as spam or phishing attempts. It can also provide a central location where administrators can set policies to manage and control email inbound or outbound communication and help protect your organisation from external threats.

2. Select the right type of email gateway

There are different types of email gateways on the market, each with different features and functionalities. Here are a few key points to keep in mind while selecting one.

  • Scalability

Make sure that your selected gateway can scale as your organisation grows.

  • Security

Ensure the gateway you select has proper security features to help protect your organisation’s sensitive data, IP, and email communications.

  • Integration

Make sure the gateway you select has the ability to integrate with your existing systems, such as your existing mail server, firewall, or SIEM. This will make it easier to implement and operate.

  • Use cases

Ensure the gateway you select supports the use cases you want to address or focus on, such as compliance, blocking malicious emails, etc.

3. Identify primary use cases for the email gateway

Once you have determined that an email gateway would be a good fit for your organisation, the next step would be to identify which specific use cases you want to focus on.

When identifying the use cases for your gateway, you should ask yourself what your primary objectives are for implementing the gateway. For example, you may want to focus on blocking malicious emails from entering your organisation’s email system or implementing regulatory compliance requirements around sending emails.

4. Implement email server protection

Email services can be hacked, but servers used to send and store the email can also be compromised. These servers can be disrupted by spam and DDoS attacks. Additionally, hackers can use them to send spam emails from your server, harming your reputation and getting you blacklisted.

It is for this reason that you should protect your email servers. Protect email servers by implementing the following techniques:

  • Specify a list of domains and IP addresses to which your mail can be safely forwarded by setting the mail relay parameter

  • Reducing spam and DDoS attacks by limiting the number of connections

  • Before accepting incoming messages, verifying the sender through reverse DNS

Your server can be protected from spammers by using content filtering.

5. Create effective spam filters

A certain amount of unwanted emails are already filtered out by modern email providers. It shouldn't stop you from making your own spam filters. Your account's spam filters allow you to further restrict what reaches your employees. Take into consideration:

  • A whitelisting tactic can be used on accounts that should only receive internal communications: Any contact not on the approved list will be blocked.

  • Users who send or receive external emails should install an email antivirus software on their computers. Most antivirus software now integrates with email to provide additional security.

  • Take a look at your spam tools to see if you need anything to supplement them. Filters like these help prevent employees from clicking on malicious links in suspicious emails.

6. Educate your users on spotting phishing emails

Educating employees on how to identify phishing emails can reduce the likelihood that an attack will be successful. Discuss how phishing attacks have evolved, such as business email compromise. Routinely conduct these trainings. They are not effective if they are only held annually. Ensure that you are up-to-date on email security every few months. Establishing clear policies on email communication can also help users avoid phishing emails.


An email gateway is a great solution for protecting your organisation’s email system from malicious emails and threats. It can help mitigate the risk of spam, phishing attempts, and malicious attachments entering your organisation’s email system.

Implementing a thorough test and control process is the best method to ensure that your email gateway is configured correctly. This ensures that any false positives are addressed before going live.

SEMNet is an established cybersecurity and IT infrastructure consulting firm that can assist you in improving performance, lowering risks, and increasing efficiency throughout your IT system. Our services include AI Automated Security Training, Cloud Access Security Broker (CASB), Cyber Risk Assessment x Security Monitoring & Analytics, End Point EDR / Patch Management, and vulnerability management solutions in Singapore. With our services, you can be confident that your IT security is in experienced hands. Please contact us today for more information about our company and products.


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