Comment by abelanger

If anyone needs commands for turning off the CF proxy for their domains and happens to have a Cloudflare API token.

First you can grab the zone ID via:

    curl -X GET "https://api.cloudflare.com/client/v4/zones" -H "Authorization: Bearer $API_TOKEN" -H "Content-Type: application/json" | jq -r '.result[] | "\(.id) \(.name)"'

And a list of DNS records using:

    curl -X GET "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records" -H "Authorization: Bearer $API_TOKEN" -H "Content-Type: application/json"

Each DNS record will have an ID associated. Finally patch the relevant records:

    curl -X PATCH "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/dns_records/$RECORD_ID" -H "Authorization: Bearer $API_TOKEN" -H "Content-Type: application/json" --data '{"proxied":false}'

Copying from a sibling comment - some warnings:

- SSL/TLS: You will likely lose your Cloudflare-provided SSL certificate. Your site will only work if your origin server has its own valid certificate.

- Security & Performance: You will lose the performance benefits (caching, minification, global edge network) and security protections (DDoS mitigation, WAF) that Cloudflare provides.

- This will also reveal your backend internal IP addresses. Anyone can find permanent logs of public IP addresses used by even obscure domain names, so potential adversaries don't necessarily have to be paying attention at the exact right time to find it.