Private IP is the same as Public IP but within a constrain network.
The LAN IP address you using at home is by definition a Private IP.
Thus within the network topology of the Private Network, all nodes participating in this network will have connectivity with each other. A good example is how you can share files and printer within you home network. If I didn't remember wrongly, MR is using a Class B private IP address for their dynamic IP subscribers.
3 Segment of address are IP reserved by IANA for use in Private Network carved from the 3 CLASS of IP address.
1. Class A : 10.0.0.0 - 10.255.255.255 <- typically found as the default address in SOHO routers, especially in Aztech.
2. Class B: 172.16.0.0 - 172.31.255.255
3. Class C: 192.168.0.0 - 192.168.255.255 <- typically found as the default address in SOHO routers
By default, all MR users are expected to access Internet via the use of a router, of course there will be exception where subscriber directly connect their PC/notebook to the ONT (doesn't work for traffic light ISP
). Thus by this default configuration, the user PC/devices will be behind a NAT device (the router). Dynamic IP users will still have to go through MR Carrier Grade NAT device, thus other users on Public IP will not be able to access MR Dynamic IP users
This is also main the reason why MR Dynamic IP users will often face more issues that their Static IP peers due to the double NAT implementation which is frown upon by Networking professional/ seasoned Networking users.
Since now, the user (regardless of Static of Dynamic IP) is behind a NAT device. In order to share out a service like FTP, a SNAT (static NAT) aka port-forwarding entry will need to be created to allow device on the public interface of the NAT device to access the device on the Internal Interface. In context of a MR dynamic IP user, by doing a port-forwarding, it will allow other MR dynamic IP user to access the service but not by any other IP as such from MR Static IP user as the Dynamic IP user is still behind another NAT device (MR likes to glorified this NAT device by calling it Carrier Grade NAT, which at the end of the day is still NAT albeit more power thats all). Thus unless MR does another SNAT for this user, no one from outside the Dynamic IP segment will be able to reach the user. By design NAT device can't NAT another IP of the same segment as itself, thus allowing a Dynamic IP users to access another Dynamic Users. Savy?
