Set custom DNS resolver

Override DNS for a host:port pair (test behind CDN/LB)

curl --resolve example.com:443:1.2.3.4 https://example.com
tool
curl21 commands
tags
curlnetworkdebug

More curl commands

  • Retry on failure
    curl --retry 5 --retry-delay 2 --retry-all-errors https://api.example.com/healthz

    Retry up to 5 times with 2s delay on any error

  • POST form data
    curl -d 'user=alice&pass=secret' -X POST https://auth.example.com/login

    Send URL-encoded form data

  • Client certificate auth
    curl --cert client.crt --key client.key --cacert ca.crt https://secure.example.com

    mTLS request with client cert and custom CA

  • Parallel downloads with xargs
    cat urls.txt | xargs -P 5 -I{} curl -sSL -o /dev/null -w '%{url_effective} %{http_code}\n' {}

    Download 5 URLs in parallel and print status codes

  • WebSocket handshake test
    curl -i -N -H 'Upgrade: websocket' -H 'Connection: Upgrade' -H 'Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==' -H 'Sec-WebSocket-Version: 13' http://localhost:8080/ws

    Verify WebSocket upgrade handshake responds with 101

all 21 curl commands