Domain and Website Monitoring: Why and How to Set It Up

Website and domain monitoring is the process of continuously tracking the availability, performance, and correct operation of web resources. Without monitoring, you are the last to learn about problems — from users, or worse, from a drop in sales. In this article, we will cover what needs to be tracked and how to properly set up a monitoring system.

Why Monitoring Is Critically Important

Every minute of website downtime costs businesses dearly. According to Gartner, the average cost of one minute of downtime for large companies exceeds $5,600. But even for small businesses, website unavailability means lost customers and trust.

Typical problems that monitoring detects:

• Complete site unavailability due to server failure
• Slow loading due to overload or database issues
• SSL certificate expiration
• Unauthorized DNS record changes
• Accessibility issues from certain regions
• HTTP errors (500, 502, 503, 504)

Types of Monitoring

1. Uptime Monitoring (Availability)

The most basic type of monitoring — checking whether the server responds to requests. The system sends HTTP requests at a set interval (usually every 1–5 minutes) and checks the response code.

What to pay attention to:

• HTTP response code — 200 means success, 5xx means a server error
• Response time — a sharp increase in TTFB may precede a failure
• Page content — checking for the presence of key elements (e.g., an order form)
• Multi-location checks — the problem may be regional

You can check your site's current response time and HTTP code using the HTTP header checker tool on enterno.io.

2. SSL Certificate Monitoring

SSL certificate expiration is one of the most common yet easily preventable problems. Browsers display a "Connection not secure" warning, and most users immediately leave the site.

What to monitor:

Use the enterno.io SSL checker to verify the certificate, chain of trust, and supported protocols.

3. DNS Monitoring

DNS record changes can indicate domain compromise or configuration errors. DNS monitoring helps detect:

• Unauthorized changes to A/AAAA records (traffic redirection)
• MX record changes (mail interception)
• Deletion or modification of TXT records (SPF, DKIM, DMARC)
• NS record changes (domain control hijacking)
• Domain registration expiration

Regularly check your domain's DNS records using enterno.io DNS Lookup. The tool shows all record types: A, AAAA, MX, NS, TXT, CNAME, and SOA.

4. Ping Monitoring and Port Checking

Ping monitoring measures network latency to the server and helps detect network-level issues that are not always visible through HTTP checks.

Which ports to check:

• 80 (HTTP) and 443 (SSL/TLS проверку) — main web ports
• 22 (SSH) — if used for administration
• 3306 (MySQL) or 5432 (PostgreSQL) — if the database is on a separate server
• 25, 465, 587 (SMTP) — for mail servers

The Ping & Port Checker tool on enterno.io lets you measure latency and check the availability of specific ports.

How to Set Up Monitoring Properly

Define Critical Points

Not everything on a site is equally important. Set priorities:

1. Homepage — the business showcase
2. Conversion pages — order forms, cart, checkout
3. API документацию endpoints — if mobile apps or integrations depend on them
4. Admin panel — for content management
5. Mail server — for client communication

Choose the Check Interval

Balance between detection speed and server load:

• Critical services — every 1–2 minutes
• Important pages — every 5 minutes
• Auxiliary resources — every 15–30 minutes
• SSL and DNS — every 6–12 hours

Configure Proper Alerts

Alerts should be timely and actionable. Recommendations:

• Use multiple channels: email, Telegram, SMS, Slack
• Set up escalation — if a problem is not resolved within 15 minutes, notify the manager
• Confirm the problem from multiple locations before sending an alert
• Configure recovery notifications, not just failure alerts
• Avoid "alert fatigue" — too many false positives dull attention

Popular Monitoring Tools

Monitoring as a Process

Monitoring is not a one-time setup but an ongoing process. Regularly:

• Review the list of monitored resources when infrastructure changes
• Analyze incident history to identify patterns
• Update threshold values based on real data
• Conduct fire drills to test response procedures
• Document runbooks — step-by-step instructions for common incidents

Monitoring Setup Checklist

1. Identify critical URLs and services
2. Set up uptime checks with appropriate intervals
3. Add SSL certificate monitoring with 30-day advance warnings
4. Configure DNS monitoring for key records
5. Verify the availability of critical ports
6. Set up notification channels (at least two)
7. Create a status page for users
8. Document response procedures
9. Run a test of the entire alert chain