Using Proxies with cURL

cURL is a powerful command-line utility for HTTP. It excellently supports all proxy types.

Basic Syntax

curl -x [protocol://]host:port URL

HTTP Proxy

# Simple request through proxy
curl -x http://proxy.example.com:8080 https://httpbin.org/ip

# With authentication
curl -x http://user:password@proxy.example.com:8080 https://httpbin.org/ip

# Or separately
curl -x http://proxy.example.com:8080 -U user:password https://httpbin.org/ip

HTTPS Proxy

curl -x https://proxy.example.com:8080 https://httpbin.org/ip

SOCKS Proxy

# SOCKS4
curl --socks4 proxy.example.com:1080 https://httpbin.org/ip

# SOCKS4A (DNS through proxy)
curl --socks4a proxy.example.com:1080 https://httpbin.org/ip

# SOCKS5
curl --socks5 proxy.example.com:1080 https://httpbin.org/ip

# SOCKS5 with DNS through proxy (recommended)
curl --socks5-hostname proxy.example.com:1080 https://httpbin.org/ip

Environment Variables

# Set proxy globally
export http_proxy=http://proxy.example.com:8080
export https_proxy=http://proxy.example.com:8080

# Now all requests go through proxy
curl https://httpbin.org/ip

# Ignore proxy for certain hosts
export no_proxy=localhost,127.0.0.1,.internal.com

Useful Options

# Show connection time
curl -x http://proxy:8080 -w "Time: %{time_total}s\n" https://httpbin.org/ip

# Ignore SSL errors
curl -x http://proxy:8080 -k https://example.com

# Set timeout
curl -x http://proxy:8080 --connect-timeout 10 https://httpbin.org/ip

# Follow redirects
curl -x http://proxy:8080 -L https://httpbin.org/redirect/3

# Save cookies
curl -x http://proxy:8080 -c cookies.txt https://example.com

# Send POST request
curl -x http://proxy:8080 -X POST -d "data=value" https://httpbin.org/post

Proxy List Check Script

#!/bin/bash
while read proxy; do
    result=$(curl -x "$proxy" -s --connect-timeout 5 https://httpbin.org/ip)
    if [ $? -eq 0 ]; then
        echo "[OK] $proxy"
    else
        echo "[FAIL] $proxy"
    fi
done < proxies.txt

Debugging

# Verbose output
curl -x http://proxy:8080 -v https://httpbin.org/ip

# Show only headers
curl -x http://proxy:8080 -I https://httpbin.org/ip