docs: Swarm.EnableHolePunching

docs/config.md

@@ -99,6 +99,7 @@ config file at runtime.
     - [`Swarm.AddrFilters`](#swarmaddrfilters)
     - [`Swarm.DisableBandwidthMetrics`](#swarmdisablebandwidthmetrics)
     - [`Swarm.DisableNatPortMap`](#swarmdisablenatportmap)
+    - [`Swarm.EnableHolePunching`](#swarmenableholepunching)
     - [`Swarm.EnableAutoRelay`](#swarmenableautorelay)
     - [`Swarm.RelayClient`](#swarmrelayclient)
       - [`Swarm.RelayClient.Enabled`](#swarmrelayclientenabled)
@@ -1279,6 +1280,21 @@ Default: `false`
 
 Type: `bool`
 
+### `Swarm.EnableHolePunching`
+
+Enable hole punching for NAT traversal
+when port forwarding is not possible.
+
+When enabled, go-ipfs will coordinate with the counterparty using
+a [relayed connection](https://github.com/libp2p/specs/blob/master/relay/circuit-v2.md),
+to [upgrade to a direct connection](https://github.com/libp2p/specs/blob/master/relay/DCUtR.md)
+through a NAT/firewall whenever possible.
+For good results, use with `RelayClient.Enabled` set to `true`.
+
+Default: `false`
+
+Type: `flag`
+
 ### `Swarm.EnableAutoRelay`
 
 Deprecated: Set `Swarm.RelayClient.Enabled` to `true`.