You do realize they all point to the same IP address, right??
No matter how many names you use, they all resolve to your public IP address.
You are correct sir if you are using it for just your home ISP connection with the default ISP provided DHCP address.
My different DDNS names go to different internet IP addresses and same IP but different directories on my hosting services.
For one ISP connection one house then with a tickle the free stuff works fine (sort of).
I remotely take care of my sister's stuff and use DDNS rather than have her do a "what is my IP address google search) especially if I am doing stuff in the middle of the morning (3 AM). I do think a lot of Cocoontech folks which deal with IT do similiar for their families wherever they are in the US or abroad. I do come from a very small family such that it is easy to do.
Each geographically autonomous location does a tickle to my no-ip account for their own unique Dynamic DNS stuff.
Relating to using PFSense no computer that accesses the internet does direct requests as all DNS requests goes to the PFSense mothership (one IP) which uses DNS forwarder and resolver services. You can also get a gold sub from PFSense which will back up your stuff and manage it if you want for a yearly fee.
1 - whatchamacallit internal device IP DNS request ===> PFSense (one IP) with DNS forwarder/resolver services ==> whichever list of DNS servers configured (multiple's of).
2 - whatchamacallit internal device IP NTP request ==> internal NTP server using multiple satellites for a stratum zero source (with no reliance on the internet).
3 - running Squid (using ClamAV subs -free for private use) and Snort (VRT sub- free for private use) on the mothership which is working very hard these days. (IE for a Cisco ASA / Barracuda /Netgear ProSafe / Juniper / SonicWall / Fortinet (well and a bunch more commercial appliances) it is paid for by whatever company). IE: just last week got to play with the newest 1U Cisco ASA. Very clean efficient looking machine. Just curious why they make the GUI such a hodgepodge collection of stuff (like a splat of art) very similar to the first web based java clients they used for the commercial switches. Definitely written by someone translating stuff from whatever to english. (there are typos in it still - very odd considering it is around a $4000 - $7000 USD or so plus appliance). Many many years ago had to write a sort of installation manual for a custom Cisco router OS that used
MATIP (plus the regular normal router stuff). Really it was a translation of ill conceived logic making it a bit difficult to do an off the shelf configuration of it and all I did was translate it to router (brouter) english.
4 - IPSec VPN can be one for many or you can individualize different IPSec tunnels it depending on your needs.
NOTE: I do not work for PFSense; just use it and a happy camper.