PDAnet on Android IP on PC is not public IP. Where does the NAT take place, PDAnet or Verizon?

Question

When using PDAnet on a PC (Win7 ultimate) to USB tether a Motorola Droid on Verizon 3G the IP address of the PC appears to be public - 64.245.171.115 (64-245-171-115.pools.spcsdns.net) - but connections show as coming from another public IP - 97.14.69.212 (212-sub-97.14.69.myvzw.com).

Someone is performing Network Address Translation - either PDAnet or within the Verizon 3G network.

Can someone tell me who is doing the NAT? Is it PDAnet or is it at Verizon?

Is there any possibility of setting up port forwarding, such that connections to the public IP 97.14.69.212 (212-sub-97.14.69.myvzw.com) are forward to the PC?

We are testing a network protocol that requires either a true public IP or forwarding a range of ports from the public Internet to the system on which the software runs (actually Linux hosted by VMware Player or Workstation on a PC running Windows).

Answer 1

I don't believe it's PDAnet - it could be but since it was initially designed around a dial-up architecture I think it's unlikely. Almost all Cellular connections are translated in some fashion though and I'd be surprised if a cellular data connection was providing a fully accessible public ip-address to a mobile device. While it is technically possible for the Cellular provider to provide [fully routable and open] public addresses there isn't a huge demand for them and from their point of view it's not usually practical, especially with ipv4. It's also something that the cellular providers will typically regard as undesirable as they really do like to exercise a significant level of traffic control on their networks and translation makes that easier. You can pay for premium data services from some providers that are more flexible but for the most part you get a tightly controlled connection, and have little choice if you are using a consumer grade data plan.

An alternative for you may be to use the [probably] translated connection to set up a VPN connection to a gateway that tunnels across the troublesome connection and provides you with exactly the sort of connection you need at the other end. You may still have issues as some Cellular providers block traffic that they recognize as VPNs unless you are paying for business use (at a higher tariff). That isn't as common as it used to be but its worth checking before wasting any time or money figuring it out.