Using curl to Fetch DNS Results

Introduces two ways to use the curl command to obtain DNS query results.
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This article presents two methods to retrieve DNS query results using curl:

  1. DNS JSON format
  2. DNS Wire Format

1. DNS JSON Format Queries

Returns DNS responses in JSON, making them easy to parse.

Google

curl -H 'accept: application/dns-json' "https://dns.google/resolve?name=baidu.com&type=A" | jq .

Cloudflare

curl -H 'accept: application/dns-json' 'https://cloudflare-dns.com/dns-query?name=baidu.com&type=A' | jq .

Aliyun

curl -H "accept: application/dns-json" "https://223.5.5.5/resolve?name=baidu.com&type=1" | jq .

dns.pub

curl -H 'accept: application/dns-json' 'https://doh.dns.pub/dns-query?name=baidu.com&type=A' | jq .

AdGuard Private DNS

# Currently unsupported

2. DNS Wire Format Queries

Returns binary DNS responses that require further parsing.

Google

curl -H 'accept: application/dns-message' 'https://dns.google/dns-query?dns=q80BAAABAAAAAAAAA3d3dwdleGFtcGxlA2NvbQAAAQAB'  | hexdump -c

Cloudflare

curl -H 'accept: application/dns-message' 'https://cloudflare-dns.com/dns-query?dns=q80BAAABAAAAAAAAA3d3dwdleGFtcGxlA2NvbQAAAQAB'  | hexdump -c

Aliyun

curl -H 'accept: application/dns-message' "https://dns.alidns.com/dns-query?dns=P8QBAAABAAAAAAAABWJhaWR1A2NvbQAAAQAB"  | hexdump -c

dns.pub

curl -H 'accept: application/dns-message' 'https://doh.dns.pub/dns-query?dns=q80BAAABAAAAAAAAA3d3dwdleGFtcGxlA2NvbQAAAQAB'  | hexdump -c

AdGuard Private DNS

curl -H 'accept: application/dns-message' 'https://public0.adguardprivate.com/dns-query?dns=q80BAAABAAAAAAAAA3d3dwdleGFtcGxlA2NvbQAAAQAB'  | hexdump -c

Parsing DNS Responses with Python

# pip install dnspython
# pip install requests
# Parsing JSON responses
import json
import requests

def query_dns_json(domain="example.com", type="A"):
  """Query DNS using JSON format"""
  url = "https://dns.google/resolve"
  params = {"name": domain, "type": type}
  headers = {"accept": "application/dns-json"}

  response = requests.get(url, params=params, headers=headers)
  return json.dumps(response.json(), indent=2)

# Parsing Wire Format responses
def query_dns_wire(domain="example.com"):
  """Query DNS using Wire Format"""
  import dns.message
  import requests
  import base64

  # Create DNS query message
  query = dns.message.make_query(domain, 'A')
  wire_format = query.to_wire()
  dns_query = base64.b64encode(wire_format).decode('utf-8')

  # Send request
  url = "https://dns.google/dns-query"
  params = {"dns": dns_query}
  headers = {"accept": "application/dns-message"}

  response = requests.get(url, params=params, headers=headers)
  dns_response = dns.message.from_wire(response.content)
  return str(dns_response)

if __name__ == "__main__":
  print("JSON query result:")
  print(query_dns_json())
  print("\nWire Format query result:")
  print(query_dns_wire())

Generating Base64-Encoded DNS Wire Format Data

# pip install dnspython
import base64
import dns.message
import dns.rdatatype

# Create a DNS query message
query = dns.message.make_query('example.com', dns.rdatatype.A)

# Convert message to Wire Format
wire_format = query.to_wire()

# Encode to base64
wire_format_base64 = base64.b64encode(wire_format).decode('utf-8')

# Print
print(wire_format_base64)