dnspython

Examples

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Get the MX target and preference of a name:

import dns.resolver

answers = dns.resolver.query('dnspython.org', 'MX')
for rdata in answers:
    print 'Host', rdata.exchange, 'has preference', rdata.preference
	      
Transfer a zone from a server and print it with the names sorted in DNSSEC order:

import dns.query
import dns.zone

z = dns.zone.from_xfr(dns.query.xfr('204.152.189.147', 'dnspython.org'))
names = z.nodes.keys()
names.sort()
for n in names:
    print z[n].to_text(n)
	      
Use DNS dynamic update to set the address of a host to a value specified on the command line:

import dns.query
import dns.tsigkeyring
import dns.update
import sys

keyring = dns.tsigkeyring.from_text({
    'host-example.' : 'XXXXXXXXXXXXXXXXXXXXXX=='
})

update = dns.update.Update('dyn.test.example', keyring=keyring)
update.replace('host', 300, 'a', sys.argv[1])

response = dns.query.tcp(update, '10.0.0.1')
	      
Manipulate domain names:

import dns.name

n = dns.name.from_text('www.dnspython.org')
o = dns.name.from_text('dnspython.org')
print n.is_subdomain(o)         # True
print n.is_superdomain(o)       # False
print n > o                     # True
rel = n.relativize(o)           # rel is the relative name 'www'
n2 = rel + o
print n2 == n                   # True
print n.labels                  # ('www', 'dnspython', 'org', '')
	      
Generate reverse mapping information

# Usage: reverse.py ...
#
# This demo script will load in all of the zones specified by the
# filenames on the command line, find all the A RRs in them, and
# construct a reverse mapping table that maps each IP address used to
# the list of names mapping to that address.  The table is then sorted
# nicely and printed.
#
# Note!  The zone name is taken from the basename of the filename, so
# you must use filenames like "/wherever/you/like/dnspython.org" and
# not something like "/wherever/you/like/foo.db" (unless you're
# working with the ".db" GTLD, of course :)).
#
# If this weren't a demo script, there'd be a way of specifying the
# origin for each zone instead of constructing it from the filename.

import dns.zone
import dns.ipv4
import os.path
import sys

reverse_map = {}

for filename in sys.argv[1:]:
    zone = dns.zone.from_file(filename, os.path.basename(filename),
                              relativize=False)
    for (name, ttl, rdata) in zone.iterate_rdatas('A'):
        l = reverse_map.get(rdata.address)
        if l is None:
            l = []
            reverse_map[rdata.address] = l
        l.append(name)

keys = reverse_map.keys()
keys.sort(lambda a1, a2: cmp(dns.ipv4.inet_aton(a1), dns.ipv4.inet_aton(a2)))
for k in keys:
    v = reverse_map[k]
    v.sort()
    l = map(str, v)     # convert names to strings for prettier output
    print k, l
	      
Convert IPv4 and IPv6 addresses to/from their corresponding DNS reverse map names:

import dns.reversename
n = dns.reversename.from_address("127.0.0.1")
print n
print dns.reversename.to_address(n)
	      
Convert E.164 numbers to/from their corresponding ENUM names:

import dns.e164
n = dns.e164.from_e164("+1 555 1212")
print n
print dns.e164.to_e164(n)