Don’t add NAT’d peers to the Routing Table

[jacobheun]

Design notes

• When adding an inbound node (inbound connection) to the routing table, perform the following tests, in this order:
  1. Reject the peer if it advertises relay addresses, or only private/localhost addresses.
     • Consider running a separate local-only DHT.
  2. Optionally, try dialing them back. We should rely on AutoNAT as our first choice, and only switch to this version if that isn't sufficient. Add a feature flag (option) to enable this feature.
     • The simplest approach to conduct a dial to a peer that we’re already connected to is to use a secondary libp2p host, like go-libp2p-autonat-svc does.
• (Optional) Enable the AutoNAT service on all nodes by default (with rate limits).
  (requires Reliable AutoNAT)

Testing mechanics

Testing with the code from the disjoint lookups and correctly terminating queries, dial up the number of undialable nodes to 95% and make sure everything works.

Success Criteria

Content and peer routing work when 90% of the network is undialable.

[aarshkshah1992]

I've only just skimmed through the paper and there are some ideas that could be of help when we get to this. I'll make sure to come up with a proposal based on the paper when we start working on this.

https://www.researchgate.net/publication/224602685_Connectivity_properties_of_Mainline_BitTorrent_DHT_nodes