VyOS ships with a DynDNS2 client via its dynamic DNS service that can target any custom server. With DNS Beacon your router stays reachable under a permanent hostname even when your WAN IP changes. Here's how to configure it via the CLI.
CLI (configure)
In the CLI: `set service dns dynamic name dnsbeacon protocol dyndns2`, then `server <API host>`, `host-name <hostname>`, `username <email>`, `password <API key>`, `address interface eth0` — then `commit; save`. On VyOS 1.2/1.3 the path is `service dns dynamic interface eth0 service …`.
Create a free DNS Beacon account, add a hostname and generate an API key — then come back and finish the setup above.
Create free account