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The State of NAT Traversal

zerotier.com · 2,030 words · saved by 1 readers

The TL;DR ZeroTier One tackles NAT traversal with a lazy approach: relaying traffic through a server while simultaneously attempting a direct UDP hole-punched connection, so only about 4% of ZeroTier traffic ends up needing relay at all. ZeroTier uses stateless connection setup and 60-second UDP broadcasts to find peers on the same local network without prior configuration. NAT history, the four

The TL;DR ZeroTier One tackles NAT traversal with a lazy approach: relaying traffic through a server while simultaneously attempting a direct UDP hole-punched connection, so only about 4% of ZeroTier traffic ends up needing relay at all. ZeroTier uses stateless connection setup and 60-second UDP broadcasts to find peers on the same local network without prior configuration. NAT history, the four NAT types and their traversability, symmetric NAT workarounds, and UPnP are all covered here, wrapped around ZeroTier’s own memorable line that NAT murders kittens. For those who don’t know, NAT…

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