How Our Monitoring Works
Sentinel checks your websites at regular intervals from multiple global locations. We verify:
- Response time
- HTTP status codes
- Content matching
- SSL certificate validity
Pro Tip
Use custom check intervals to balance between quick detection and resource usage.
Bot Identification
Our monitoring bot identifies itself using a User-Agent header that includes a link to our bot information page. This allows server administrators to verify the legitimacy of our requests.
Visit our Bot Information page for the complete list of IP addresses used by our monitoring infrastructure.
Firewall & WAF Whitelisting
If your website uses a firewall, WAF (Web Application Firewall), or CDN with bot protection (like Cloudflare), you may need to whitelist our monitoring bot to ensure accurate uptime checks.
You can either whitelist our IP addresses or configure your firewall to allow requests with our User-Agent string. See our Troubleshooting guide for detailed instructions for popular firewalls and CDNs.
Getting 403 Errors?
If your monitor shows "403 Forbidden" errors, your server is likely blocking our bot. This doesn't mean your site is down - it just means our monitoring requests are being rejected. Visit the Troubleshooting section for solutions.