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dennis-tra / nebula

🌌 A network agnostic DHT crawler, monitor, and measurement tool that exposes timely information about DHT networks.
Apache License 2.0
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Does this crawler support crawler the node behind the NAT? #23

Closed yourmoonlight closed 1 year ago

yourmoonlight commented 2 years ago

Hi guys, this crawler looks amazing. I am curious about how do we crawl the node behind the nat?

dennis-tra commented 2 years ago

Hi @yourmoonlight, thanks!

Generally, this crawler does not crawl peers behind NATs as they are usually not publicly reachable.

If peers detect that they are behind a NAT device they start operating in DHT-Client mode. However, only DHT-Server nodes end up in routing tables which Nebula uses to recursively enumerate the DHT. So, the current implementation does not allow systematic crawling of DHT-Client nodes.

Please note, if there was a systematic approach to enumerate DHT-Client peers there are NAT hole punching mechanisms. See this recent blog post:

https://blog.ipfs.io/2022-01-20-libp2p-hole-punching/

I hope this has answered your question :)

yourmoonlight commented 2 years ago

Oh I see，gracias～