Improve email security with Plesk: The best strategies for 2025

Email security with Plesk is crucial in 2025 to successfully fend off targeted attacks, spoofing and digital industrial espionage. With the right settings in the Plesk panel, emails can be systematically authenticated, controlled and protected against misuse.

Key points

• DNS authentication: Consistently activate and monitor SPF, DKIM and DMARC
• TLS encryptionSet up SSL certificates for all domains and check updates
• Antispam & AntivirusUse combined filter strategies with whitelists and score rules
• Access policiesRestrict Plesk access to secure IPs and enforce password security
• Monitoring & UpdatesPerform blacklist checks, log analyses and system updates regularly

Activate basic e-mail protection under Plesk

Plesk provides all the central functions needed to secure your own e-mail system against manipulation. After installing the Plesk Email Security extension, I always start with the basic configuration. This includes the average spam score, the blocking of recognized spam communication and the configuration check of all domains. Only when SPF, DKIM, DMARC, MX, DNSBL and RDNS are marked "green" is my system stable. I make sure that all clients set SPF to "v=spf1 +a +mx include:_spf.hostname.de ~all". I generate DKIM keys myself in Plesk, DMARC is available as "v=DMARC1; p=quarantine; rua=mailto:[email protected]". This effectively blocks spoofing.

Combining filter rules and spam protection

The anti-spam filter is my central protective shield against everyday attacks. Plesk allows the flexible control of SpamAssassin and blocks threats before they are delivered to the mailbox. I manage the block and whitelist regularly and adjust the scoring values depending on the mailbox requirements. This saves viewing costs and reduces misclassifications. I have also defined rules for certain senders and keywords - for example, every email with a request for payment outside of usual partners is automatically marked as "[Pot. Phishing]".

Encrypting data traffic: TLS for e-mail transport

When it comes to e-mail security, it's not just who sends, but also how. I set up valid SSL certificates for all the domains I use. This is the only way I can ensure that emails are not manipulated or viewed while in transit. TLS encryption is mandatory - for both incoming and outgoing connections. The Plesk interface helps with simple uploading and validation via Let's Encrypt or individual certificates. I check regularly: Does the certificate expire? Are there any old domains that do not have an active SSL? This not only protects my systems - it also noticeably increases the deliverability of receiving services.

Security guidelines for user accounts

Access often weakens email environments more than technology. In Plesk, I use the security policy with password complexity "Very strong". This means that capital letters, numbers and at least one special character are mandatory. In addition, I activate, if possible, Multi-factor authentication via OTP apps. Access to the Plesk panel is restricted to internal office IP addresses. Remote access is only possible via VPN. This also prevents admin brute force attacks or credential stuffing. In connection with this, I recommend activating Fail2Ban. Instructions on how to do this can be found at this guide to the Plesk Fail2Ban configuration.

Access control and DNS hardness

Sensitive DNS structures require more than basic protection. I prohibit my customers from setting up subzones in third-party DNS areas - a well-known gateway for phishing. I also set up a blacklist of suspicious domain names that are frequently misused for typosquatting. To secure the Plesk panel, I use the firewall function under Tools & Settings. I use it to block unauthorized ports and admin access outside defined networks. For convenient administration, I recommend this Firewall guide for Plesk.

Extended user rules: More control over mailboxes

Plesk offers many automation options in the email area. I use custom filters to route business-critical emails to defined folders. For example, applications end up directly in the personnel folder, while social media notifications are hidden. During my absences, out-of-office notifications, forwarding or collective accounts automatically activate preset responses. This relieves the burden on support and eliminates the need for manual intervention.

Securing mailing lists: Sending serial emails in a legally compliant manner

Serial emails risk SPAM classification if they are sent unprotected or without double opt-in. Plesk offers the option of setting limits per user under Email settings - e.g. 200 emails per 60 minutes. I adhere strictly to data protection regulations: transparent unsubscription, proof of opt-in and clear data protection wording. This means that even newsletter mailing lists remain secure and GDPR-compliant.

Promoting cooperation between technology and users

A system is only as secure as its weakest link. That's why I hold regular training courses for employees. They learn: report suspicious emails, never open ZIPs or EXEs, check URLs before clicking. Plesk helps with implementation through greylisting - incoming emails from unknown senders are accepted with a delay, which slows down many botnets. To secure external WLANs, I recommend that business users only check their emails via secure VPN connections.

Monitoring, diagnostics and troubleshooting

If there are problems with deliverability or filtering, there are clear checkpoints. I check whether the server IP is on a public blacklist, whether sufficient storage space is available and whether the TLS certificate is valid. I also use log analysis to check which rule contributed to the filtering. I also regularly use tools such as Plesk Health Monitor to analyze system reserves and performance and to detect or resolve bottlenecks in good time.

Performance, security and availability: a good host makes all the difference

A secure server environment starts with the right hosting partner. I trust in webhoster.debecause the provider delivers top values for availability, integration and security in 2025 - especially in combination with Plesk.

Provider	Availability	Security	Configuration	Performance
webhoster.de	99,99 %	Very high	Intuitive	Excellent
Provider B	99,5 %	High	Medium	Good
Provider C	98,9 %	Medium	Base	Medium

A good supplement is this overview of Manage Plesk e-mail accountsto administer user rights and mail accounts securely and quickly.

New challenges in 2025 and beyond

It is already apparent that attackers are using increasingly sophisticated methods to manipulate email communication or to infiltrate malware unnoticed. I am increasingly observing attacks that use AI-generated phishing emails. Such fake messages appear even more credible as they are tailored to individual recipients and imitate their language or writing style. This is where it pays to continuously update Plesk and apply strict spam rules so that even AI-based attempts at deception are recognized and blocked. I am also noticing the growing trend of zero-day phishing. Attackers are using completely new vulnerabilities that are not yet publicly known to launch targeted attacks. This makes it all the more important to promptly install security updates and actively analyze logs. Only those who keep a constant eye on the server analysis can quickly identify unusual patterns. Plesk provides the necessary tools for this directly in its interface, so that I can quickly report and rectify critical anomalies. Cloud integration also increases complexity. Many companies combine Plesk with external cloud services, which often leads to new points of attack if access rights and authorizations are not set up properly. I recommend protecting every cloud connection with firewalls, access tokens and clearly defined DNS entries so as not to leave an open door for attackers. At the same time, it is worth keeping the documentation of all workflows up to date so that no security-relevant steps are forgotten when onboarding new employees. Looking ahead to 2025 and the years thereafter, I therefore see increasing networking and specialization of attack patterns. Anyone who lags behind here risks not only data loss, but also a serious loss of trust from customers and business partners. An elective approach that continuously focuses on training, system maintenance and proactive defense remains the key to success.

DNS security and global trends

SPF, DKIM and DMARC are already established standards in the email context. Nevertheless, some statistics show that too many domains are still operated without these important security components. I encourage all users to activate DNSSEC for their domains and to rely on robust DNS management. DNSSEC prevents the manipulation of DNS queries by digitally signing responses. Although Plesk cannot automatically manage DNSSEC in every hosting package, it still makes sense to activate DNSSEC for domains where possible. This counteracts DNS spoofing and cache poisoning. Another trend concerns the global fragmentation of network traffic. Countries and regions sometimes create very specific data protection and cybersecurity laws. This can lead to confusion for international business partners - for example when emails are routed via different network nodes. To protect the integrity and confidentiality of emails, I rely on stricter TLS standards and, wherever possible, encrypted connections from the client to the final recipient. At the same time, I advocate uniform guidelines that clearly communicate how data is processed and protected within the company. Load balancing plays a role, especially with DNS DDoS attacks on the rise. Even if a mail server is configured securely, it must be able to withstand high data traffic so that it does not collapse under load. A strategic distribution of mail traffic across several servers or a backup mail server can tip the scales in times of DDoS attacks and prevent outages.

Automated reports and systematic control

Many admins underestimate how helpful automated reports can be. I have activated regular delivery reports in Plesk, which provide me with information about the number and quality of incoming and outgoing emails. Email statistics tell me where critical spikes occur, which inboxes receive a particularly high number of spam attempts and whether a domain suddenly generates an unusually high number of outgoing emails. The latter would be a signal of a possible compromise. In addition to Plesk, the monitoring ecosystem offers log file analyses and warnings about potential CPU or RAM bottlenecks. I have a summary sent to me once a day so that I can quickly assess whether all services are running smoothly. In the event of conspicuous spike values, I react immediately and check whether certain IPs are conspicuous or whether certain mailboxes have been compromised. Daily controlling saves a lot of time, especially for companies with a large volume of emails, because it provides clear indications and recurring patterns can be quickly identified. It is important that these reports do not disappear into data nirvana. If you only receive them in passing but never evaluate them, you will lose the biggest advantage. Regular team meetings or brief discussions with those responsible help to resolve any problems at an early stage. This minimizes potential damage and strengthens confidence in your own infrastructure.

Advanced security concepts for user access

Beyond pure password management, every organization should establish an extended security concept in 2025. I rely on a form of zero-trust approach for this: no user account or session is assumed to be trustworthy per se, but access rights are continuously checked and only granted for the scope required in each case. Together with Plesk, this can be achieved by setting up dedicated roles and user groups, for example. This means that an administrator for DNS tasks is not automatically granted full access to all databases or email inboxes. At the same time, I am focusing more on securing IMAP and SMTP access. When users work remotely, this poses an increased risk. That's why I usually enforce VPN connections for external access and secure SMTP auth strictly via TLS. Of course, passwords should never be transmitted in plain text. Plesk supports all of these models, provided they are specifically activated and the interaction with the firewall is precisely configured. The aim is always to keep email traffic in a protected tunnel, while unauthorized requests from outside are not even allowed through.

Integration of external security tools and compliance

Depending on the industry, email communication is often supplemented by additional security levels. Whether virus scanners at application level, cloud security services or special threat intelligence systems: Anyone using several tools in parallel must also integrate them cleanly into Plesk in order to avoid conflicts or performance losses. I make sure that the anti-spam rules from Plesk do not overlap with those of other services, otherwise emails end up in spam twice or misclassifications become more likely. Another aspect is adherence to industry-specific compliance regulations. In the healthcare sector, for example, this includes the GDPR plus the respective national health data protection laws that regulate the handling of patient data. The same applies to law firms and notaries. Here, it is crucial to be able to log who had access to which emails and when. Plesk offers its own logs in which access and configuration changes are listed. If you systematically evaluate these logs or forward them to compliance offices if necessary, you are on the safe side in an emergency.

Data volume, quota management and effectiveness

An often underestimated factor in mail operations is the volume of data. In 2025, companies often send large attachments or media files - whether presentations, videos or graphics. I set clear quotas per mailbox and domain so that mails are not stored indefinitely. Mailboxes that are too large complicate backup strategies and slow down the mail server. In Plesk, I can control quotas centrally and define specific warning thresholds so that users are informed in good time before their mailbox overflows. This is linked to a sensible archiving strategy. For example, older emails of a certain age can be automatically moved to an archive or saved as a backup. This reduces the load on the live server, speeds up the search in the current mailbox and minimizes the risk of sensitive data being stored in an unstructured way. I combine Plesk functions with external archiving tools here, but without opening up new gateways. It is important that each new component is properly secured and configured, for example with dedicated API keys or encrypted data transfer.

Summary for ongoing operations

The days of installing a security update once a year and leaving everything else running are long gone. If you want to be successful in 2025 and beyond, you need to understand email security as a permanent process. I rely on carrying out a short audit every month, during which I clarify the following questions: Are all certificates still valid? Are SPF, DKIM and DMARC working? Have access authorizations been adjusted for personnel changes? Established routine processes pay off in the long term because you simply maintain a secure basic framework and can react quickly if necessary. A clearly documented escalation protocol is also worthwhile. If a compromise does occur, the team needs to know exactly who to inform, how to isolate the servers and which measures have priority. Well thought-out emergency plans ensure that nothing is forgotten, even in stressful situations, and that the consequences remain manageable.

My conclusion for 2025: actively shape the level of safety

Email security with Plesk requires discipline, understanding of attack vectors and systematic maintenance. I combine DNS authentication, encryption, user behavior and diagnostic tools to secure all levels of my communication system. If you actively implement this checklist and adapt your strategy, you can withstand the security pressure - and benefit from stable, trustworthy communication.