Hello.
I’m implementing a VPN service which is using IPFS for node discovery and as fallback network (when it’s impossible to connect peers directly). And I’m going to call it “InterPlanetary VPN” (“ipvpn”). Do I have permission on such naming of my project (without any restrictions to my project)?
I won’t tell the interplanetary police if you don’t.
Sorry for the year-long delay on responding to this 
– answering also for the future.
Short answer: please don’t.
Long answer:
There is a family of projects named interplanetary-something and abbreviated like IPFS, IPLD, IP_ _. It is our intention to make sure protocols/projects named this way are very closely linked, about distributed web data structures, follow the interplanetary principle[0], and have closely linked communities. Basically, close enough to be parts of the same thing.
In general, we strongly discourage naming things Interplanetary-something or abbreviating things IPXX to avoid brand confusion, and causing problems for the community, and the users. In some cases, it makes good sense and it is ok, notably IPWB (thanks for asking first!). In some rare cases we’ve had to ask people to rename because their projects were too far away, or were perceived to be bad actors in our community, and would damage the reputation and good standing of IPFS. (we keep the IPFS trademark for this kind of community and user protection)
Separately, i think that if you’re making a VPN and using the node-discovery of libp2p (the library IPFS uses), then you really want to associate your project with libp2p, not IPFS per se. I would suggest peer-vpn or p2p-vpn or similar.
[0] interplanetary principle: distributed computing systems should be designed to work across planets – this means designing for large latencies, connectivity outages, unavailability of common internet services, to work across vastly different use case domains and nations. IPFS itself is very close to it, though its connectivity layer – libp2p – isn’t there yet).