BNETDocs
C>S 0x1E W3GS_REQJOIN
Message Id:0x1E
Message Name:W3GS_REQJOIN
Direction:Client to Server
Used By:Warcraft III The Frozen Throne, Warcraft III Reign of Chaos
Format:

(UINT32) Host Counter (Game ID)
(UINT32) Entry Key (used in LAN)
(UINT8) Unknown
(UINT16) Listen Port
(UINT32) Peer Key
(STRING) Player name
(UINT32) Unknown
(UINT16) Internal Port
(UINT32) Internal IP

Remarks

A client sends this to the host to enter the game lobby.

The internal IP uses the Windows in_addr structure which is thus used by the sockaddr_in structure.

Comments
Caaaaarrrrlll

From cen:

@BNETDocs Staff message by h3rmit, forwarding

W3GS_REQJOIN has proved to be inaccurately documented in 1.29
https://bnetdocs.org/packet/446/w3gs-reqjoin
it is 1 byte more in 1.29
and I found what it is: wrong documentation
the (UINT32) Unknown they describe is not fixed-length
A client sends this to the host to enter the game lobby.
so, (UINT32) Unknown is  2 bytes in 1.29 if he is to be believed, maybe that will give a hint to what this unknown is