Submitting dynamic DNS updates in python

I'd been looking for an equivalent to the UNIX nsupdate facility (https://linux.die.net/man/8/nsupdate) for RFC2136 compliant updates (to a standard Windows or UNIX DNS server), but in python.

I found
https://github.com/rthalley/dnspython

Although the examples were extremely limited (there was nothing much on creating PTR records), I was able to achieve what I needed eventually. The below is tested in python2.7

import dns.update
import dns.query
import dns.reversename
import dns.rdatatype
 
def create_dns_record():
    ### Create A Record
    dns_domain = "%s." % (domain) # Set the domain name with a trailing dot (to stop auto substitution of zone)
    update = dns.update.Update(dns_domain) # Prepare the payload for DNS record update in the given zone/domain (dns_domain)
    update.replace(new_hostname, TTL, 'A', new_ipaddress) # Inject the record details into the dns.update.Update class
    response = dns.query.tcp(update, PRIMARY_DNS_SERVER_IP, timeout=5) # Submit the new record to the DNS server to apply the update
    ### Create reverse entry (PTR)
    reventry = dns.reversename.from_address(new_ipaddress) # Neat function to generate a reverse entry
    revzone = ''
    revzone = '.'.join(dns.name.from_text(str(reventry)).labels[3:]) # Specify the reverse lookup zone based on the reverse IP address.
    # The labels[X:] property allows you to specify which octet to use.
    # e.g. 3: will apply the record to the 10.in-addr.arpa zone, whereas 1: will apply it to the 72.23.10.in-addr.arpa zone
    raction = dns.update.Update(revzone) # Prepare the payload for the DNS record update
    new_host_fqdn = "%s.%s." % (new_hostname, dns_domain) # Although we are updating the reverse lookup zone, the record needs to point back to the ‘test.example.com’ domain, not the 10.in-addr.arpa domain
    raction.replace(reventry, TTL, dns.rdatatype.PTR, new_host_fqdn) # Inject the updated record details into the the class, preparing for submission to the DNS server
    response = dns.query.tcp(raction, PRIMARY_DNS_SERVER_IP, timeout=5) # submit the new record to the DNS server to apply the update
 
domain = "test.example.com"
new_ipaddress = "10.23.72.44"
new_hostname = "server01"
PRIMARY_DNS_SERVER = "8.8.8.8"
TTL = "1200"
create_dns_record()

Tag

• Python
• dns