I'm coming back with this issue because I just changed my ISP and got FTTH up & running... Drawbacks are:
- I'll need to replace my good'old WNDR3700v2 with a more powerfull router

- No more DynDNS management directly available with my ISP box

So I used Gargoyle again as a workaround. And after having browsed the logs, I've seen that all dyndns requests are properly managed but those to aruljohn.com.
Is there a way to blacklist aruljohn.com?