PRTG – P8 PRTG Tutorial Website Monitoring Step by Step

Website availability is critical for every business. Even a few minutes of downtime can impact reputation, SEO rankings, and revenue. Without proper monitoring, you may not even know your website is down until users start complaining.

In this tutorial, you’ll learn how to Monitor Website uptime and availability using PRTG Network Monitor. This step-by-step guide explains how to configure HTTP and HTTPS sensors to track website status, response time, SSL certificate health, and performance metrics.

Website monitoring is essential for detecting downtime before users are affected. PRTG allows IT administrators to receive instant alerts when a website becomes unavailable or slow. In this guide, we demonstrate how to add a website to PRTG and configure monitoring thresholds correctly.

You’ll also learn best practices for monitoring public websites and internal web services.

This tutorial is ideal for network administrators, system engineers, and IT professionals who need reliable website monitoring.

Follow this guide to ensure your websites are always available and performing properly.

🌐 Step 1: Add Device

First, add your website as a device inside PRTG.

IPv4/DNS Name:

This registers the domain so sensors can be attached and monitored properly.

📊 Step 2: Add Sensors

Now we configure the essential sensors required to properly Monitor Website availability and performance.

2.1 HTTP Advanced Sensor

Add Sensor → HTTP Advanced

Why choose this?

• Supports HTTP + HTTPS
• Has response time
• Has status code (200/301/403/500…)
• Most flexible

Setting Value

URL

Timeout: 30s
Method: GET
User Agent: Default
Follow redirects ✔

The HTTP Advanced sensor is the core sensor for website monitoring because it provides detailed metrics about availability and performance.

2.2 SSL Certificate Sensor

Add Sensor → SSL Certificate

This sensor monitors:

• SSL expiration date
• Chain errors
• CN mismatch

After creating, edit again → Channel Setting

Disable revoked warnings due to using SSL Let’s Encrypt (sensors will not be able to check)

This prevents unnecessary alerts caused by Let’s Encrypt revocation check limitations.

2.3 Website Speed Monitoring (Important)

Inside HTTP Advanced, you’ll find multiple important channels used to Monitor Website performance.

Response Time

General response measurement from request to full completion.

Download Time

Measures how long it takes to download page content.

Loading Time (Very Important)

TIME TO LOAD THE ENTIRE PAGE

• From connection → HTML loading
• Reflects:
o Nginx
o PHP
o MySQL
o Reverse proxy

This is the main channel for measuring website speed.

Threshold example:

3000 → 3 seconds (yellow)
5000 → 5 seconds (red)

If loading time consistently exceeds 3–5 seconds, performance optimization is required.

Time to First Byte (TTFB)

Time from request → receiving the first byte

• Reflects:
o Slow backend processing
o Slow PHP/MySQL
o Long reverse proxy wait

TTFB is crucial for diagnosing slow website issues from the server side. If TTFB is high, the bottleneck is usually backend-related.

Download Bandwidth

Average download speed

• Less important for small websites
• Only useful if:
o Large files
o Media site

For typical WordPress business websites, this metric is secondary.

Bytes Received

Represents page size.

Used to:

o Detect bloated pages
o Detect injected data/code

Unexpected increases in page size may indicate malware injection or misconfiguration.

Downtime

Website DOWN time

• PRTG automatically adds
• No threshold required

This channel directly shows when your website becomes unavailable.

2.4 Check the Actual WordPress Content

Sometimes:

• Server is alive
• But WordPress has a blank page error

In this case, the HTTP request may return status 200, but the page content is broken.

To detect this, configure:

Bytes Received

• Lower Warning: < 0.05
• Lower Error: < 0.01

Blank page / PHP fatal error → Bytes are almost = 0

This is an extremely effective method to detect white screen errors even when the server appears online.

🚀 Best Practices to Monitor Website Effectively

To properly Monitor Website infrastructure:

• Always combine HTTP Advanced and SSL sensors

• Set realistic loading time thresholds

• Monitor TTFB to detect backend issues early

• Watch Bytes Received for anomalies

• Configure alerts via email or mobile push

• Monitor from an external probe for public websites

Public websites should ideally be monitored from outside your internal network to detect ISP or routing issues.

📌 Final Thoughts

You have now configured a complete website monitoring setup using PRTG Network Monitor.

By adding your domain as a device and deploying HTTP Advanced and SSL Certificate sensors, you gain full visibility into uptime, response time, SSL validity, backend performance, and potential content issues.

With properly configured thresholds for loading time, TTFB, and Bytes Received, you can detect downtime, slow performance, blank page errors, and SSL problems before users are impacted.

A website is often the public face of your infrastructure. When you properly Monitor Website performance with PRTG, you move from reactive troubleshooting to proactive monitoring.

In the next tutorial, we will continue expanding PRTG monitoring capabilities with more advanced configurations.