SMTP Monitoring with PRTG

SMTP – simple mail transfer protocol – is email’s postal service. When you press “send” within Outlook, Gmail, or another email client, your email is sent to an SMTP server. The server then connects to your recipient's SMTP server and transfers the content of your emails.

PRTG’s preconfigured SMTP sensor monitors key email parameters by establishing a connection with your SMTP servers. Add the sensor to your monitoring environment, pick your preferred settings, and enter your authentication credentials. You can then configure the monitoring process, including your HELO ident and whether to send a test email with each check.

Ideally, server response times should be 200 milliseconds or under. But, in practice, response times can be much quicker or much slower. It depends on various factors, including the way your network is configured, bandwidth, availability, latency, and even who your email service provider is.

PRTG uses preconfigured sensors to monitor the sending and receiving of emails that originate in your system. It starts by sending an email to a given email address. This allows you to immediately see whether – and how fast – the email reaches the recipient, and how long it takes for the recipient to retrieve the email via POP3. If the delivery and retrieval are successful, the email is automatically deleted.

PRTG tracks emails by leveraging regular expression matching within log files for advanced analysis. This feature allows PRTG to identify specific patterns, anomalies, or issues in email logs, such as delivery failures, unusual access patterns, or errors. By analyzing these logs, PRTG can help you spot potential security threats or performance issues in your email system early on, enabling you to address them before they escalate into serious problems.

PRTG’s biggest benefit is that it’s an all-in-one monitoring solution (as your higher-ups would put it). In other words, it enables you to keep an eye not just on SMTP servers, but on every single component that forms part of your network, without having to switch between different monitoring environments. With support for all major protocols – including SNMP, WMI, Windows performance counters, flow, SSH, HTTP and HTTPS, FTP, and more – PRTG can monitor every component and parameter imaginable, no matter how complex your network is.

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, for example the traffic of a switch port, the CPU load of a server, or the free space on a disk drive. On average, you need about 5-10 sensors per device or one sensor per switch port.