ddclient

ddclient is a long-standing, Perl-based Dynamic DNS client that keeps DNS records updated when your public IP changes. It supports a wide roster of DNS providers and APIs, allowing both A and AAAA updates so IPv4 and IPv6 hosts remain reachable. The client can discover your current address via network interfaces or external check services, which is crucial for NAT’d home connections. It runs as a daemon or from cron, with configurable intervals, SSL/TLS for provider communication, and robust logging to aid troubleshooting. A single configuration file defines multiple hosts, credentials, and per-record options, making complex setups straightforward. In practice, ddclient turns dynamic residential or small-office internet links into stable hostnames for VPNs, home labs, and self-hosted services.