1. Use –resolve Option
The –resolve option allows you to manually specify the IP address for a domain, effectively overriding DNS resolution.
Steps:
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Use the following syntax: curl –resolve <hostname>:<port>:<IP_address> <URL>
Key Notes:
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This method inserts the mapping into cURL’s internal DNS cache.
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Useful for testing specific server responses without modifying system-wide DNS settings.
2. Use –connect-to Option
The –connect-to option redirects requests from one hostname and port to another, bypassing DNS entirely.
Steps:
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Use the following syntax: curl –connect-to <source_host>:<source_port>:<target_host>:<target_port> <URL>
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Example: curl –connect-to example.com:443:load1.example.com:443 https://example.com Redirects traffic for example.com to load1.example.com.
Key Notes:
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Unlike –resolve, this resolves the target hostname (load1.example.com) dynamically.
3. Use Custom DNS Server with –dns-servers
If your cURL build supports it, you can specify a custom DNS server for resolving domain names.
Steps:
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Use the following syntax: curl –dns-servers <DNS_IP> <URL>
Example:
Key Notes:
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Ensure your cURL version supports this option (requires c-ares backend).
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Verify compatibility using curl –version.
Best Practices
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Use –resolve or –connect-to for testing environments or debugging.
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Avoid modifying system-wide DNS settings unless necessary.
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Always verify your cURL version and features (curl –version) before using advanced options like –dns-servers.
These methods allow precise control over DNS resolution, making them ideal for debugging, testing, or working in custom network setups.
