This Cloudflare Worker script provides a DNS over HTTPS (DoH) service with intelligent ECS (EDNS Client Subnet) handling for improved CDN performance.
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ECS Extraction: The worker extracts two sets of ECS options from URL:
- Client IP: The actual IP address of the client making the request.
- Alternative IP: Typically, the external IP address of a VPN connection.
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Dual DNS Resolution: The worker performs two DNS resolutions for each request, one using the client IP and one using the alternative IP.
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Intelligent Response Selection: The worker compares the IP addresses returned in both DNS responses:
- Same Country Match: If the IP address returned using the client IP is located in the same country as the client, that response is chosen. This prioritizes local CDN nodes for optimal performance.
- Alternative IP Response: If the client IP response doesn't match the client's country, the response obtained using the alternative IP is chosen. This ensures content delivery even when using a VPN or experiencing routing issues.
- Improved CDN Performance: By intelligently selecting the best DNS response based on client location, the worker ensures requests are routed to the most optimal CDN nodes.
- Enhanced Privacy: Utilizing DoH encrypts DNS queries, preventing eavesdropping and manipulation.
- Seamless VPN Integration: The worker's dual resolution approach ensures uninterrupted content delivery even when using a VPN.
This worker is designed for deployment on the Cloudflare Workers platform. Here are the steps to deploy:
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Install dependencies:
npm install
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（Optional）Login to Wrangler:
npx wrangler login
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Download, create, and import the GeoIP database:
You need to set following env vars before run the import script:
export MAXMIND_ACCOUNT_ID= export MAXMIND_LICENSE_KEY= export CLOUDFLARE_ACCOUNT_ID= export CLOUDFLARE_API_TOKEN= # Disable .workers.dev domain if you do not want to expose it in Github Action logs. # export WORKERS_DEV=false
Note: The following permissions for cloudflare token are needed to run the script, you can visit here to create a new token:
Account/Worker Scripts/Edit Account/D1/EditThen, run the script:
./import-geoip.sh
The script will do the following tasks
- Download the GeoLite2 Country database from MaxMind and extract it to the
./tmpdirectory. - Create a D1 database on Cloudflare and import the downloaded database into the D1 database.
- Download the GeoLite2 Country database from MaxMind and extract it to the
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Configure wrangler.toml:
mv tmp/wrangler.toml . -
Deploy:
npm run deploy
Replace doh.subdomain.workers.dev with your domain name after deploying the script to cloudflare workers.
https://doh.subdomain.workers.dev/client-ip/223.5.5.5/client-country/CN/alternative-ip/8.8.8.8/dns-query
Contributions are welcome! Please feel free to open issues or submit pull requests.