In this article, we'll introduce you to the top 10 mail server monitoring tools that can help safeguard your email system, ensuring uninterrupted service, quick issue resolution, and compliance with industry regulations. Mail server monitoring is a critical aspect of maintaining a smoothly running and secure email infrastructure for organizations. Without proper monitoring, organizations risk facing numerous challenges, including email service disruptions, security breaches, inefficient resource allocation, and compliance issues. These challenges can lead to financial losses, reputational damage, and operational inefficiencies. To mitigate these risks and maintain a robust email infrastructure, system administrators and IT professionals can turn to mail server monitoring tools. These tools offer a range of features, including real-time performance tracking, proactive issue identification, and the ability to optimize resource allocation. Whether hosted on-premises or in the cloud, these tools are indispensable for any organization relying on email as a mission-critical application. Frequently Asked Questions About Mail Server Monitoring What are Mail Server Monitoring Tools? Mail server monitoring tools are software applications or services that help system administrators and IT professionals keep a close eye on their email servers' performance, availability, and security, be they hosted on-premises or in the cloud. These tools are crucial for ensuring that email services run smoothly and efficiently, as email is a mission-critical application for many, if not all, organizations. They can range from simple status monitors that tell you if the server is up or down, to tools to calculate the round-trip time for email delivery, to services that can keep tabs on the size of a mailbox or check for specific messages (and contents) inside. Of course, there are also countless more sophisticated packages that can measure resource utilization, monitor the message queue, do error and log analysis, or use historical data to chart performance trends, helping you identify when additional resources or new servers are needed to support increased email traffic. Keep in mind that some of the tools listed here are specific to the Microsoft Exchange Server, one of the most used platforms by businesses and organizations to manage email, calendars, contacts, and tasks. Others also support universal protocols, such as IMAP4, POP3, and SMTP. Take advantage of the free trials offered by most tools, and always check for compatibility with your infrastructure before making a commitment. Why Should You Invest in Mail Server Monitoring? There are many reasons to invest in mail server monitoring. Here are five of them, in no particular order. Performance optimization: continuous monitoring can help you pinpoint issues and identify opportunities for optimization that will improve the performance of your mail servers, sometimes without the need for hardware upgrades. Security: monitoring allows you to spot early signs of uncommon behavior or usage patterns indicative of an intrusion attempt or ongoing attack. This will give you time to react and deploy countermeasures before a data breach occurs. Resource allocation: find out where resources are being underutilized or overutilized, allowing you to redistribute them according to real needs to ensure the most effective usage of your systems. Proactive maintenance: monitoring allows you to detect and fix potential issues before they become critical and result in outages that may affect the performance of your applications or even the profitability of your business. Regulatory compliance: businesses that handle sensitive information, like financial or healthcare data, need to meet strict regulatory standards that specify how this information is stored and handled. Monitoring will allow you to prove compliance with these standards and secure approvals that may be crucial to keeping your business running. What to Look for When Choosing Mail Server Monitoring Tools? Broadly speaking, there are 5 main features you need to look out for when choosing mail server monitoring tools. Keep in mind that this may vary according to your specific needs. The capability to monitor many aspects of your mail servers at once. A centralized display of information from many sensors for better observability. Customizable alerts and automated notifications when alerts are triggered. Native and automated reporting features so that you can keep co-workers and management "in the loop". A free trial period, so you can attest to how the tool works with your network infrastructure. How to do Mail Server Monitoring? There are many email server monitoring tools, from as many different vendors, which may focus solely on a single aspect of the task or offer this capability as a subset of a broader range of features. We present a few of them below, in no particular order. The Best Mail Server Monitoring Tools PRTG Paessler PRTG is often called the Swiss army knife of the monitoring world. It is based on basic monitoring elements called "sensors". One sensor usually monitors one measured value in your network, e.g. the traffic of a switch port, the CPU load of a server, the free space of a disk drive, and so on. With more than 250 built-in sensors for various tasks, device types, and use cases, you would be hard-pressed to find something you can't monitor with PRTG. Plus, you can mix and match sensors, and even deploy custom ones, to create monitoring solutions specific to your needs. There are sensors to monitor internal parameters, the mail queue, backups, and public folders on Exchange servers, and also sensors for IMAP, POP3, and SMTP servers. Need to monitor a mailbox for messages from a specific sender or with a specific subject, like those sent by backup software? That is easy as well. The Exchange Mail Queue sensor on PRTG The information gathered by PRTG is shown on a centralized dashboard with all the relevant metrics. You can set alerts based on threshold values, with notifications delivered by text (SMS) or email if those values are exceeded. There is also an automatic reporting feature, so you can keep management and co-workers informed. PRTG Network Monitor is available on a perpetual license basis or monthly subscription plans with PRTG Hosted Monitor. The software requires a computer running Windows Server 2012 R2, 2016, 2019, 2022, or Windows 11. There is a 30-day free trial of PRTG, with all features available during this period, no credit card is needed. ManageEngine Applications Manager The ManageEngine Applications Manager suite of monitoring tools includes modules to monitor your mail servers, with special attention given to Microsoft Exchange Servers: it can measure the memory and disk utilization to optimize their performance. It supports monitoring of various server roles like Mailbox, Client Access, Unified Messaging, Hub Transport, and Edge Transport. It also allows the monitoring of mailbox and public folder databases, helps with troubleshooting Outlook connectivity, and can monitor emails, voicemails, faxes, calendar information, and contacts. Monitoring POP, IMAP, and SMTP connections on ManageEngine Applications Manager This tool is also available as a mobile app for iOS and Android, with features such as an overview of all monitors, groups, and subgroups with availability and health status, notifications for critical and warning alarms and push notifications for health and availability alerts. There is also a mobile web client, suitable for any smartphone with a modern web browser. ManageEngine Applications Manager is SaaS, with pricing available by quote. It runs on Windows Server 2012 R2, 2016, 2019, 2022, Windows 10 or Windows 11, and also on Linux distributions like CentOS, Debian, Fedora, openSUSE, Oracle Linux, Red Hat Enterprise Linux (7 and 8), SUSE Linux Enterprise and Ubuntu. There is a 30-day free trial available. Nagios XI Nagios XI is a complete IT infrastructure monitoring tool that can monitor your mail servers and much more, including applications, services, operating systems, and network protocols. Its web-based interface is configurable and easy to use, providing at-a-glance access to monitoring information. Wizards help you easily monitor POP3, IMAP, SMTP, and Microsoft Exchange servers (including service states, protocol availability, and performance metrics). There is also a wizard to monitor email delivery, and many other add-ons related to email monitoring. The monitoring interface on Nagios XI It is possible to create multiple users with different levels of access to the web interface, so stakeholders can easily access relevant information, but nothing more. As in other tools, in case of outages, alerts can be sent to IT staff and end-users via email or mobile text messages. Nagios XI is available in two editions, "Standard" and "Enterprise", and there is a fully functional 30-day free trial. It only runs natively under Linux, more specifically distributions like CentOS, Red Hat Enterprise Linux (RHEL), Ubuntu, or Debian. However, it can be run on Windows servers using virtualization solutions like VMWare, Virtual Box, or Hyper-V. SolarWinds Server and Application Monitor The SolarWinds® Server & Application Monitor (SAM) is a complete infrastructure monitoring package that can help you monitor email servers, plan mailbox capacity, and manage email issues. This includes the capability to test email delivery and measure the round-trip time for protocols such as MAPI, POP3, IMAP4, and SMTP. It can identify email traffic spikes and server CPU bottlenecks, diagnose replication, storage, RPC requests, and database capacity issues, and use real-time and historical performance data to troubleshoot mail server problems. Monitoring an Exchange server on SolarWinds Server and Application Monitor Data is presented in an integrated, "single-pane-of-glass" dashboard, providing insights into "systems, applications, and infrastructure performance, regardless of where they reside". This information can be visualized and correlated across the environment, with dynamic baselining to define what is normal operation and what should trigger an alert. SolarWinds Server and Application Monitor is offered on a flexible licensing model, with subscription or perpetual licensing, according to your needs. System requirements for a locally hosted server include Microsoft Windows Server 2012, 2012 R2, 2016, 2019, or 2022 and Microsoft SQL Server 2016 or greater. A free, fully functional 30-day trial is available. Zabbix Zabbix is a free and open-source monitoring package that can do a lot, including mail, server, cloud, application, services, and network monitoring into one tool. It has integrations that allow for the monitoring of POP, SMTP, and IMAP servers, and also specific mail software such as MDaemon, Postfix, Sendmail, Exchange, and Zimbra, among others. "Smart thresholds" allow your team to do root cause analysis for issues and anomaly detection, and there is an AI-based trend prediction system that not only informs you that your mail server will run into performance issues, but also how much time you have left until a threshold is reached. The alerting system is very flexible, supporting not only SMS and email, but also modern communication platforms like Slack, Microsoft Teams, Telegram, and more. Messages can even be customized according to the type and role of the recipient. Data visualization on the Zabbix Dashboard The Zabbix server can only run on Linux, on-premises, or in the cloud. Supported distributions are Alma Linux, CentOS, Debian, Oracle Linux, Raspberry Pi OS, Red Hat Enterprise Linux, Rocky Linux, SUSE Linux Enterprise Server, and Ubuntu, both for x64 and arm64 architectures. Zabbix may be Open Source and free, but you pay for the technical support. There are five support tiers (Silver, Gold, Platinum, Enterprise, and Global I), each one with different levels of availability, response times, and amount of incidents and support contacts. Netwrix Netwrix Auditor is a comprehensive Microsoft Exchange monitoring software that simplifies the auditing process for both on-premises Exchange Server and Exchange Online. This tool is designed to help organizations efficiently monitor and secure their email systems by providing real-time insights and proactive alerts, making it easier to identify and respond to potential security threats and operational issues. It automatically notifies users about critical events that could impact the security and availability of their email systems, such as changes to Exchange configurations, non-owner activity in important mailboxes, and the addition of remote domains. Additionally, it identifies high-risk user accounts and provides a unified view of anomalous activity alerts across all audited systems, enhancing the detection of potential threat actors. Reviewing permission changes on Netwrix Mail Monitor This tool allows organizations to investigate operational incidents and troubleshoot issues more efficiently by providing an interactive search feature for quick data analysis. Intuitive dashboards offer a high-level view of changes and help identify unusual surges in user activity. Netwrix Auditor also simplifies compliance audit preparation by providing ready-to-use compliance reports mapped to common regulatory standards, making it easier to demonstrate compliance to auditors. Pricing for Netwrix Auditor is only available by request. The software requires Windows Server 2012, 2012 R2, 2016, 2019, or 2022, or Windows 8.1 or 10. There is a 20-day free trial available. Opsview Monitor Opsview Monitor is a system and network monitoring software platform designed to help IT teams monitor and manage their infrastructure and applications. It provides a comprehensive set of tools and features for monitoring the performance and availability of various components in an IT environment, including servers, network devices, applications, and cloud services. It offers continuous email system monitoring, ensuring 24/7/365 availability, with automatic identification of on-premises and cloud-based mail systems. It also promptly identifies the root cause of issues and monitors SMTP, IMAP, and POP3 services, as well as popular SaaS-based email applications like Google Apps and Office 365. Operational configurations can be automated, customizable dashboards are provided, and SLA reports can be generated while offering alternative notification methods beyond email for system failures. A monitoring dashboard on Opsview Monitor Monitoring is done via add-ons called "Opspacks". The Exchange Server Monitoring Opspack, for example, lets you check server status, mail flow, database metrics, and client connectivity. The Mail Server Monitoring one allows for connectivity checks for IMAP4, POP3, and SMTP servers, and also a DNS blacklist check. Besides packs maintained by Opsview, this tool can also use plugins and add-ons freely available on the Nagios Exchange. Opsview Monitor is SaaS available in three plans: a cloud-hosted one, starting at 150 hosts, and two on-premises plans, for companies with less than 300 (SMB) or more than 400 (Enterprise) hosts. Supported operating systems for on-premises installation are Debian 10.x, Red Hat Enterprise Linux (RHEL) 7.x or 8.x, CentOS 7.x, Oracle Linux 7.x or Ubuntu 18.04 or 20.04. ENow ENow Mailscape is a monitoring package focused on Microsoft's collaboration tools: besides Exchange and Microsoft 365 monitoring and reporting, it also features Active Directory monitoring and Microsoft 365 license optimization. It offers a visual approach to Exchange monitoring, with a single pane of glass view for the entire messaging environment. Using synthetic transactions, it can monitor the mail flow, replication, and all core components of your email infrastructure, helping you identify and isolate issues faster. Exchange server monitoring on ENow It can monitor the disk and storage performance, internet, internal, and cloud mail flow, database, and system health and performance. All this data can be fed into customizable reports (with more than 250 of them built-in), including server reports to ensure SLA compliance, client access reports, and message traffic reports. Pricing for ENow is not immediately available on the developer's website. A free trial is available, but there is no information about the duration of the trial period. MXAlerts MXAlerts is a service that just monitors the most essential feature of your email server: the capacity to send and receive email. The service automatically sends your server an email every few minutes, and your server automatically replies. If the service doesn’t hear back from your server, it will alert you that something’s not right. This is known as "round-trip monitoring", and is one of the simplest ways to monitor an email server, but maybe simple is all you need. Since the alerts are delivered to an email address of your choice, you can even monitor your mail servers using your smartphone. MXAlerts is the simplest of all monitoring tools in this article MXAlerts is a cloud-based SaaS, so there is nothing to install, with a very simple and clear pricing structure based on the number of servers being monitored: the higher the number of servers being monitored, the lower will be the per-server cost. There is a 15-day free trial available. LogicMonitor LogicMonitor offers email service monitoring for health metrics, including round-trip time and transit time. There is also a set of modules that provides comprehensive out-of-the-box monitoring for the Microsoft Exchange mail and calendaring server, and Microsoft Office 365 monitoring. The server monitoring feature can gather metrics such as CPU utilization, disc space, and memory usage, correlating your mail server performance with the performance of the operating system and storage devices. It can trend the resource usage of your exchange server, monitor client access requests, database latency, IO and cache size, transport queues, alert status, and much more. Exchange server monitoring on LogicMonitor An intelligent alerting system can detect changes and anomalies across your infrastructure, such as server log events that could lead to service issues, common configuration changes, or patch updates that could disrupt connectivity, and reduces alert noise by focusing on "the right insights at the right time". LogicMonitor is SaaS, but pricing isn't immediately clear: the website directs interested users to "get a quote", without details on available plans and their capabilities. Several additional services are offered, and volume discounts are mentioned. There is a 14-day free trial available. Conclusion Among all these, our favorite mail server monitoring tool is Paessler PRTG, as it "ticks all the boxes" in our list of desired characteristics, and streamlines your workflow by enabling you to monitor all of your infrastructure with a single tool. The built-in sensors cover many of the main use cases, without the need to purchase extras, so it can monitor your mail servers, but also your network, services, IoT devices, cloud infrastructure, and much more. And it is extensible, which means you can deploy third-party sensors, or even develop your own, to cover specific needs. That means you can do away with having to rely on a variety of individualized solutions, which can carry potential risks such as conflict with your current workflow and even network security issues. It really is a "Swiss army knife" of the monitoring tools.