NAT Traversal Protocol (Pia)

Pia Protocols > NAT Traversal

Up to Pia version 5.10, the protocol port was used to determine the message type.

Protocol Port	Description
1	Probe request
2	Probe reply
3	Dummy packet

In Pia version 5.11 and later, all packets are sent through port 0 and always contain the NatProbeData structure.

The following version numbers are advertised during the connection request:

Pia version	Version
5.19 - 5.43	0

Probe request

Offset	Size	Description
0x0	16	NatProbeData

Probe reply

Offset	Size	Description
0x0	16	NatProbeData

Dummy packet

Offset	Size	Description
0x0	5	"Dummy"

NatProbeData

Offset	Size	Description
0x0	4	Service variable id
0x4	1	Probe type (0=request 1=reply, 255=dummy)
0x5	3	Padding
0x8	8	System time (OSGetSystemTime on Wii U, nn::os::GetSystemTick on Switch)

5.11 - 5.43:

Offset	Size	Description
0x10	4	Variable id