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FakeDNS (Python3)
#!/usr/bin/python3
__author__ = 'Francisco Santos'
# URL: https://code.activestate.com/recipes/491264-mini-fake-dns-server/
import socket
class DNSQuery:
def __init__(self, data):
self.data=data
self.dominio=''
tipo = (ord(data[2]) >> 3) & 15 # Opcode bits
if tipo == 0: # Standard query
ini=12
lon=ord(data[ini])
while lon != 0:
self.dominio+=data[ini+1:ini+lon+1]+'.'
ini+=lon+1
lon=ord(data[ini])
def respuesta(self, ip):
packet=''
if self.dominio:
packet+=self.data[:2] + "\x81\x80"
packet+=self.data[4:6] + self.data[4:6] + '\x00\x00\x00\x00' # Questions and Answers Counts
packet+=self.data[12:] # Original Domain Name Question
packet+='\xc0\x0c' # Pointer to domain name
packet+='\x00\x01\x00\x01\x00\x00\x00\x3c\x00\x04' # Response type, ttl and resource data length -> 4 bytes
packet+=str.join('',[chr(int(x)) for x in ip.split('.')]) # 4bytes of IP
return packet
if __name__ == '__main__':
ip='192.168.1.1'
print('pyminifakeDNS:: dom.query. 60 IN A %s' % ip)
udps = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
udps.bind(('',53))
try:
while 1:
data, addr = udps.recvfrom(1024)
p=DNSQuery(data)
udps.sendto(p.respuesta(ip), addr)
print('Respuesta: %s -> %s' % (p.dominio, ip))
except KeyboardInterrupt:
print('Finalizando')
udps.close()
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