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 and response time.
Website monitoring is critical for detecting downtime before users are affected.
PRTG allows IT administrators to receive instant alerts when a website becomes unavailable.
In this video, 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.
Follow this guide to ensure your websites are always available and performing properly.

1. Add Device

IPv4/DNS Name: tsf.id.vn

2. Add Sensors

2.1 HTTP Advanced

Why choose this?

• Supports HTTP + HTTPS

• Has response time
• Has status code (200/301/403/500…)

• Most flexible

Setting Value
URL https://tsf.id.vn/
Timeout 30s
Method GET
User Agent Default
Follow redirects ✔

2.2. SSL Certificate

Monitor:

• 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)

2.3. Website Speed ​​Monitoring (Important)

In HTTP Advanced, you’ll find:

• Response Time

• Download Time

Loading Time: TIME TO LOAD THE ENTIRE PAGE
• From connection → HTML loading

• Reflects:
o Nginx
o PHP
o MySQL
o Reverse proxy
Main channel for measuring website speed

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

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
Used to diagnose slow website issues from the server

Download Bandwidth: Average download speed
• Less important for small websites
• Only useful if:
o Large files
o Media site

Bytes Received: Page size
• Used to:

o Detect bloated pages
o Injected data Code

Downtime: Website DOWN time
• PRTG automatically adds
• No threshold required

2.4. Check the actual WordPress content

If you are worried about the following cases:

• Server is alive

• But WordPress has a blank page error
Bytes Received

• Lower Warning: < 0.05

• Lower Error: < 0.01
Blank page / PHP fatal error → Bytes are almost = 0