Como obter resultados de DNS usando curl

Introdução a dois métodos de usar o comando curl para obter resultados de consulta DNS.
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Este artigo apresenta duas maneiras de usar o comando curl para obter resultados de consulta DNS:

  1. Formato JSON DNS
  2. Formato Wire Format DNS

1. Consulta no Formato JSON DNS

Retorna a resposta DNS no formato JSON, facilitando a análise.

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

# Não suportado no momento

2. Consulta no Formato DNS Wire Format

Retorna a resposta DNS em formato binário, que requer análise posterior.

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

Usando Python para analisar respostas DNS

# pip install dnspython
# pip install requests
# Analisar respostas no formato JSON
import json
import requests

def query_dns_json(domain="example.com", type="A"):
  """Consulta DNS usando o formato JSON"""
  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)

# Analisar respostas no formato Wire Format
def query_dns_wire(domain="example.com"):
  """Consulta DNS usando o formato Wire Format"""
  import dns.message
  import requests
  import base64

  # Cria uma mensagem de consulta DNS
  query = dns.message.make_query(domain, 'A')
  wire_format = query.to_wire()
  dns_query = base64.b64encode(wire_format).decode('utf-8')

  # Envia a solicitação
  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("Resultados da consulta em formato JSON:")
  print(query_dns_json())
  print("\nResultados da consulta em formato Wire Format:")
  print(query_dns_wire())

Gerando dados codificados em Base64 no formato DNS Wire Format

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

# Cria uma mensagem de consulta DNS
query = dns.message.make_query('example.com', dns.rdatatype.A)

# Converte a mensagem para o formato Wire Format
wire_format = query.to_wire()

# Converte para base64
wire_format_base64 = base64.b64encode(wire_format).decode('utf-8')

# Imprime
print(wire_format_base64)