DynamicDNS should allow "@" at hostname
No-ip has the ability to update one of several IP addresses of a round-robin DNS A record. This is done adding a "@<label>" suffix at hostname. Eg.
However, trying to add such hostname in services_dyndns_edit.php results in the following error:
The following input errors were detected: The Hostname contains invalid characters.
Confirmed on pfSense 2.1.5