Domain Monitoring Basics - HTTP Checks vs Ping vs DNS

Domain Monitoring Basics - HTTP Checks vs Ping vs DNS

This guide explains different types of domain monitoring and when to use each. Understanding the differences helps you set up comprehensive monitoring.

For multi-location monitoring, see Global Agent Monitoring.

Types of Domain Monitoring

When to Use Each Type

HTTP Check (Most Common)

# Tests full stack: DNS + Network + Web server + App
curl -I https://example.com

Use for: Production websites, APIs, any HTTP service
Catches: Most problems users would experience

Ping (ICMP)

# Tests: Network path only
ping -c 1 example.com

Use for: Basic connectivity, servers without web services
Catches: Server down, network issues
Misses: Application problems, port issues

DNS Check

# Tests: Name resolution only
dig example.com +short

Use for: Detecting DNS propagation issues, hijacking
Catches: DNS failures, wrong records
Misses: Everything else

Recommendation

For most websites, use HTTP check as primary (catches most issues) plus ping as secondary (faster detection of complete outages).

Method 1: Check URL Availability with curl Command

The curl command is a standard tool for checking website availability.

Basic Availability Check

To check if a URL is accessible:

# Check URL availability
curl -I https://example.com

# Check with timeout
curl -I --max-time 10 https://example.com

This shows HTTP response code, headers, and response time.

Check Response Code

To get just the HTTP response code:

# Get HTTP response code
curl -o /dev/null -s -w "%{http_code}\n" https://example.com

# Check multiple URLs
for url in https://example.com https://api.example.com; do
  CODE=$(curl -o /dev/null -s -w "%{http_code}" $url)
  echo "$url: $CODE"
done

This helps verify if websites return expected HTTP codes.

Method 2: Check URL Availability with wget Command

The wget command can also check website availability.

Basic Availability Check

# Check URL availability
wget --spider --timeout=10 https://example.com

# Check with response code
wget --spider --server-response --timeout=10 https://example.com 2>&1 | grep "HTTP/"

This verifies URL accessibility and shows response codes.

Method 3: Check URL Availability with ping Command

While ping checks network connectivity, it doesn't verify HTTP availability:

# Check network connectivity
ping -c 4 example.com

# Check if domain resolves
host example.com

This verifies network connectivity but not HTTP availability.

Method 4: Automated Domain and URL Availability Monitoring with Zuzia.app

Manually checking URL availability works for occasional verification, but for production websites, you need automated monitoring that checks availability from multiple locations and alerts you when sites go down. Zuzia.app provides comprehensive URL availability monitoring through global agents.

How Global Agent Monitoring Works

Zuzia.app uses the URL monitoring module to check website availability automatically. The system uses three geographically distributed agents (Poland, New York, Singapore) to check availability of each URL from different locations. All data is stored historically, allowing you to analyze availability from different locations and identify regional issues.

Setting Up URL Availability Monitoring

1. Add URL in Zuzia.app Dashboard

   • Navigate to your Zuzia.app dashboard
   • Click "Add URL"
   • Enter your website URL (e.g., https://example.com)
   • Choose "URL" check type - availability is checked automatically by 3 agents

2. Configure Alert Thresholds

   • Set alert threshold (e.g., response code != 200 or timeout)
   • Choose notification channels (email, webhook, Slack, etc.)
   • Configure escalation rules for critical availability issues

3. Automatic Global Monitoring

   • System automatically starts monitoring from all locations
   • You'll receive alerts when site is unavailable or returns errors
   • Historical data tracks availability from each location

AI-Powered Availability Analysis

If you have Zuzia.app's full package, AI analysis is enabled. The AI automatically detects availability problems from specific locations and can suggest optimizations based on availability patterns and response time data.

Method 5: Advanced URL Availability Monitoring Techniques

Monitor Multiple URLs

To monitor multiple URLs:

# Check multiple URLs
for url in https://example.com https://api.example.com https://admin.example.com; do
  CODE=$(curl -o /dev/null -s -w "%{http_code}" --max-time 10 $url)
  if [ "$CODE" != "200" ]; then
    echo "ALERT: $url returned $CODE"
  fi
done

This helps monitor multiple URLs simultaneously.

Check Response Times

To monitor response times:

# Check response time
curl -o /dev/null -s -w "Time: %{time_total}s\n" https://example.com

# Alert if response time > 2 seconds
TIME=$(curl -o /dev/null -s -w "%{time_total}" --max-time 10 https://example.com)
if (( $(echo "$TIME > 2.0" | bc -l) )); then
  echo "ALERT: Slow response time: ${TIME}s"
fi

This helps detect performance issues affecting availability.

Compare Availability Across Locations

By storing availability data from multiple locations in Zuzia.app, you can compare availability from different geographic regions to detect regional issues.

Real-World Use Cases for URL Availability Monitoring

Website Downtime Detection

Detect website failures quickly:

# Check website availability
CODE=$(curl -o /dev/null -s -w "%{http_code}" --max-time 10 https://example.com)
if [ "$CODE" != "200" ]; then
  echo "ALERT: Website unavailable, HTTP $CODE"
fi

Set up Zuzia.app to check URLs every few minutes from all locations and alert immediately when sites go down.

Regional Availability Issues

Detect region-specific availability problems:

# Check availability from different locations (simulated)
# Zuzia.app does this automatically with global agents

Use Zuzia.app's global agent data to identify if availability issues affect specific regions, helping diagnose CDN or hosting problems.

Uptime Monitoring

Track website uptime:

# Track availability over time
CODE=$(curl -o /dev/null -s -w "%{http_code}" --max-time 10 https://example.com)
echo "$(date): $CODE" >> /tmp/availability-$(date +%Y%m%d).txt

Use Zuzia.app's historical data to calculate uptime percentages and track availability trends.

Common Mistakes to Avoid

Mistake 1: Monitoring Only from One Location

Problem: Monitoring URL availability from only one location misses regional issues that affect users in specific geographic areas while working fine elsewhere.

Solution: Monitor from multiple geographic locations. Zuzia.app's global agents (Poland, New York, Singapore) provide comprehensive coverage to detect regional availability problems that single-location monitoring would miss.

Mistake 2: Setting Alert Thresholds Too High

Problem: Only alerting when websites are completely down (HTTP 500) misses partial failures, slow response times, or HTTP errors (4xx) that still impact user experience.

Solution: Set alert thresholds for multiple conditions - HTTP codes != 200, response times > 2 seconds, timeouts, and SSL certificate errors. This ensures you detect all availability issues, not just complete downtime.

Mistake 3: Not Monitoring All Critical URLs

Problem: Only monitoring the main website URL misses API endpoints, admin panels, and CDN URLs that are also critical for application functionality.

Solution: Monitor all critical URLs including main website, API endpoints, admin panels, CDN URLs, and third-party integrations. Each URL should have its own monitoring configuration based on importance and requirements.

Mistake 4: Ignoring Response Time Trends

Problem: Only checking if URLs are available without monitoring response times misses gradual performance degradation that impacts user experience before complete failure.

Solution: Monitor both availability and response times. Use Zuzia.app to track response times from all locations and set alerts for slow response times. Historical response time data helps identify performance trends and plan optimizations.

Mistake 5: Not Correlating Availability with Server Metrics

Problem: Investigating availability issues without checking server resources (CPU, RAM, disk) misses root causes that affect both availability and performance.

Solution: Correlate URL availability with server resource metrics. When availability issues occur, check CPU, memory, disk, and network metrics to identify root causes. Use Zuzia.app's comprehensive monitoring to view both availability and server metrics together.

Best Practices for URL Availability Monitoring

1. Monitor from Multiple Locations

Monitor URL availability from multiple geographic locations. Zuzia.app's global agents (Poland, New York, Singapore) provide comprehensive coverage to detect regional issues.

2. Monitor Regularly

Check URL availability every few minutes for critical websites. Less critical sites can be checked every 15-30 minutes. Use Zuzia.app automated monitoring to ensure continuous checks.

3. Set Appropriate Alert Thresholds

Set different alert thresholds:

• Alert on HTTP codes != 200
• Alert on timeouts
• Alert on slow response times (> 2 seconds)
• Alert on SSL certificate errors

4. Monitor All Critical URLs

Monitor all critical URLs including:

• Main website
• API endpoints
• Admin panels
• CDN URLs
• Third-party integrations

5. Track Availability Trends

Use Zuzia.app's historical data to track availability trends over time. Understanding availability patterns helps identify recurring issues and plan improvements.

Troubleshooting Common URL Availability Issues

Website Unavailable

If a website is unavailable:

1. Check from multiple locations: Verify if issue is global or regional
2. Check DNS: host example.com or dig example.com
3. Check server status: Verify server is running
4. Check firewall: Ensure ports are open
5. Review server logs: Check for errors

Regional Availability Issues

If availability issues affect specific regions:

1. Check CDN configuration: Verify CDN is working correctly
2. Check DNS: Verify DNS propagation
3. Check firewall rules: Ensure no geo-blocking
4. Review network routing: Check BGP and routing issues
5. Contact hosting provider: Report regional issues

Slow Response Times

If response times are slow:

1. Check server resources: CPU, memory, disk
2. Check database performance: Query optimization
3. Check CDN performance: Verify CDN caching
4. Review application code: Optimize slow endpoints
5. Consider scaling: Upgrade server capacity

Related guides, recipes, and problems

• Related guides
  • Monitoring Setup

FAQ: Common Questions About Monitoring Domain and URL Availability

How often is URL availability checked?

By default, URL availability is checked every few minutes from each of the three locations in Zuzia.app. You can change the frequency in check settings. For critical websites, consider more frequent checks to ensure rapid detection of downtime.

What happens if a website is unavailable from one location?

You'll receive notifications when a website is unavailable from any location or returns an error. This helps detect regional availability problems that might affect users in specific geographic areas while working fine elsewhere.

Can I monitor multiple URLs?

Yes, you can add multiple URLs in Zuzia.app and all will be monitored simultaneously. Each URL has its own alert thresholds, allowing you to customize monitoring per URL based on importance and requirements.

How can I see availability trends over time?

Zuzia.app stores all availability data historically in its database, allowing you to view availability trends over time. You can see historical data showing availability from different locations on different dates, calculate uptime percentages, identify when downtime occurred, and track availability patterns to improve reliability.

What's the difference between availability and uptime?

Availability refers to whether a website is accessible at a specific moment, while uptime is the percentage of time a website is available over a period. Availability checks verify if sites are up right now, while uptime calculates availability percentage over time (e.g., 99.9% uptime means site was available 99.9% of the time).

Does Zuzia.app use AI to analyze availability patterns?

Yes, if you have Zuzia.app's full package, AI analysis is enabled. The AI can detect patterns in availability, identify recurring downtime issues, predict potential availability problems before they occur, and suggest optimizations or detect infrastructure problems based on availability data and machine learning algorithms.

Can I see response times from different locations?

Yes, Zuzia.app tracks response times from all three global agents (Poland, New York, Singapore), allowing you to compare response times across locations. This helps identify if performance issues are regional or global, and optimize CDN or hosting configurations accordingly.

What should I do if my website is unavailable?

If your website is unavailable, immediately check server status, verify DNS resolution, check firewall rules, review server logs for errors, and verify hosting provider status. Use Zuzia.app's historical data to see when downtime started and correlate with recent changes. For comprehensive troubleshooting, see Website Unavailable Down for detailed solutions.

How can I improve website availability?

Improve website availability by monitoring continuously from multiple locations, setting up automated failover systems, using CDN services, implementing load balancing, optimizing server performance, monitoring server resources (CPU, RAM, disk), and responding quickly to alerts. Use Zuzia.app's availability data to identify patterns and plan improvements proactively.

Can I monitor API endpoints and not just websites?

Yes, Zuzia.app can monitor any URL accessible via HTTP/HTTPS, including API endpoints, webhooks, and REST APIs. Simply add the API endpoint URL in Zuzia.app, configure expected response codes (e.g., 200 for success), and set up alerts for unexpected responses or timeouts. This helps ensure your APIs remain available and responsive.