How can I monitor the origin server?

If you're using Cloudflare (or any reverse proxy) your uptime checks may only reflect the availability of the proxy, not your actual origin server. This can mask issues (e.g. HTTP 500 server down errors) if it's serving cached pages or a custom error page. To ensure real uptime accuracy you should also monitor the server behind the proxy.

Here's how to configure Oh Dear to monitor your backend/origin server directly.

Option 1: Configure your uptime check to bypass reverse proxy using a direct origin hostname

This works best when origin server has a static IP or a dedicated hostname.

1. Create a DNS A/AAAA record like origin.example.com and disable proxying (e.g. gray cloud in Cloudflare).
2. Restrict access to that hostname via firewall to Oh Dear's IPs only.
3. Add a new site in Oh Dear using origin.example.com.
4. Add custom header settings (e.g., X-OhDear: true) to whitelist/check traffic internally

Option 2: Use a private uptime check

Set up a route on the origin (e.g. /oh-dear-uptime) that:

• Is authenticated (e.g. basic auth or token)
• Has restricted access via firewall to Oh Dear's IPs only
• Is not cached or proxied (use page rules or cache bypass logic)
• Configure your uptime check in Oh Dear with HTTP Basic Auth or bearer token settings (remember to set the path to /oh-dear-uptime)

We suggested restricting access to origin checks to Oh Dear’s IP addresses and/or using authentication or custom headers (X-OhDear: true) to identify valid monitoring requests.