Drawbacks of mail gateways, antispam filters, and DKIM: what should you do?
Email remains one of the most widely used tools for both businesses and individual users. However, with widespread use, the volume of spam and cyber threats targeting this channel has also grown. To combat these risks, organisations implement various security measures, including mail gateways, antispam filters, and DKIM (DomainKeys Identified Mail).
Although these solutions are effective, they are not without drawbacks. In this article we explore some of the challenges associated with these technologies and how they affect both technical and non-technical users.
The double-edged sword of antispam filters
Antispam filters are essential to keep inboxes clear of unwanted mail. However, their effectiveness can become a problem if not configured properly. For everyday users, a notable drawback is legitimate email landing in the spam folder, which can mean lost important messages.
From a technical perspective, configuring an effective antispam filter requires a careful balance: strict enough to block spam, flexible enough to let valid mail through. That process can be complex and needs ongoing tuning as spammers adopt new tactics.
Mail gateway: comprehensive protection
A mail gateway sits between your network and the outside world, scanning and filtering all email traffic. Although it adds an extra security layer by filtering suspicious messages and blocking potential threats, implementation and management can be difficult. For typical users, a mail gateway is usually invisible; nevertheless, issues such as delivery delays or blocked attachments can be frustrating. Technically, administrators must tune policies that are sometimes overly restrictive, causing unnecessary blocks—or, worst case, letting threats slip through.
Configuration risks
DKIM adds a digital signature to email so recipients can verify that a message truly comes from the domain it claims. Although it is a powerful tool against email spoofing (phishing), implementation is not trivial. For end users, DKIM’s impact is almost invisible, but it is fundamental in fighting fraudulent email. Technically, DKIM requires DNS and cryptography knowledge; misconfiguration can cause messages to be rejected or marked unauthenticated, harming domain reputation and deliverability.
SPF: an additional layer of protection
Alongside DKIM, the SPF record (Sender Policy Framework) plays a crucial role in email authentication. SPF lets administrators specify which servers may send mail for their domain, helping prevent spammers from using forged addresses. Incorrect SPF configuration can cause legitimate mail to be rejected and disrupt communication. Like DKIM, maintaining an effective SPF record requires ongoing monitoring and updates as IP addresses and sending policies change.
Antispam filters, mail gateways, SPF, and DKIM all depend heavily on accurate configuration and continuous maintenance. Technical administrators must stay alert to updates and changes in attacker tactics, which may require frequent tuning of filtering policies and DKIM keys. End users should also remember that although these systems are designed to protect them, they are not infallible. They should check spam folders regularly and report any anomalies to IT so the system keeps working correctly.
Security and usability: finding the balance
Balancing security and usability across mail gateways, antispam filters, SPF, and DKIM is essential in the security infrastructure of any organisation’s email. Although they provide valuable protection against threats, they also introduce challenges that must be managed carefully to avoid harming email usability. Keeping security and functionality in balance ensures users enjoy a secure, efficient email experience without compromising communication or productivity.
Join us soon for part 2 on antispam!