Download of PhDDNS 1.4.37502 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac app was originally produced by Shanghai Best Oray. The application lies within Internet & Network Tools, more precisely Network tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
PhDDNS establishes a connection with the private network server through the cloud server and maps the private network port to the cloud to realize all kinds of Internet application services based on domain name. There is no need for broadband operators to assign public network IP or for router to set up port mapping.
You may want to check out more Mac applications, such as AirportTraffic, QuickWho or Throttled Pro, which might be similar to PhDDNS.