Useful `dig` and `curl` commands

script.sh

# Query any record
dig A paulogdm.com
dig NS paulogdm.com
dig CNAME www.paulogdm.com

# Query any record using a specific DNS resolver
dig A paulogdm.com @1.1.1.1
dig A paulogdm.com @8.8.8.8

# Query record with a trace of the DNS resolution
dig NS paulogdm.com @1.1.1.1 +trace

# Get headers
curl https://paulogdm.com -I

# Get a specific header
curl https://paulogdm.com -I | grep etag

# Make a POST request
curl -d '{"key1":"value1"}' -H "Content-Type: application/json" -X POST http://paulogdm.com/api

# Check if SSL is working as expected from the Vercel server
# Useful for "Zero Downtime" migrations.
curl https://paulogdm.com --resolve paulogdm.com:443:76.76.21.21 -I