DNS updates without DDNS

DDNS is pain, most of the times. It's not reliable and you may end up breaching something you did not expect to be breached. Therefor pdns has a even more dangerous way to modify the zones. There is an API.

Poor mans dns updater

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#!/usr/bin/env python3
from isc_dhcp_leases import Lease, IscDhcpLeases
import requests, json

PDNS_API="http://127.0.0.1:8081/api/v1/servers/localhost/zones/my.lan."
leases = IscDhcpLeases('/var/lib/dhcp/dhcpd.leases')

for mac, lease in leases.get_current().items():
    d={"rrsets":[]}
    if not lease.valid: continue
    ip_addr=lease.ip
    if lease.hostname!="":
        d['rrsets'].append(
            {
                "name": f"{lease.hostname}.my.lan.",
                "ttl": 60,
                "type": "A",
                "changetype": "replace",
                "records": [
                    {
                        "content": f"{lease.ip}",
                        "disabled": False,
                    },
                ],
            }
        )
    d['rrsets'].append(
        {
            "name": f"mac-{mac.lower().replace(':','')}.my.lan.",
            "ttl": 60,
            "type": "A",
            "changetype": "replace",
            "records": [
                {
                    "content": f"{lease.ip}",
                    "disabled": False,
                },
            ],
        }
    )
    requests.patch(PDNS_API, json.dumps(d), headers={'X-API-Key': 'PASSWORD'})

This is not a product, but a proof of concept.

This script runs every few seconds and updates the DNS zone for the local network.