Run these commands as root on the production host.

Run and monitor

Check the installed version and cron entry:

/opt/prod/mydynip/bin/mydynip --version
cat /etc/cron.d/mydynip

To run immediately as root:

/opt/prod/mydynip/bin/mydynip

Both ipify and ifconfig.me must return the same public IPv4 address. Failed requests, invalid responses, or disagreement prevent DNS changes. Unchanged addresses produce no output. Overlapping runs are skipped using a file lock.

The saved IP and record names are written only after all DNS commands succeed. Failures exit nonzero and are retried on the next cron run. Delete and add are separate operations: an add failure can leave the name without an A record until a retry succeeds. Multiple names are not updated atomically.

Cron sends output to syslog with the tag mydynip. On systems using journald:

journalctl -t mydynip

The saved state is a cache, not a continuous DNS audit. If someone manually changes a managed A record, remove /opt/prod/mydynip/data/state.json to force the next update.

Nadim-Daniel Ghaznavi

Running and monitoring

Run and monitor