BNETDocs
C>S 0x02 SID_STOPADV
Message Id:0x02
Message Name:SID_STOPADV
Direction:Client to Server
Used By:Starcraft Original, Starcraft Broodwar
Starcraft Shareware, Starcraft Japanese
Diablo Retail, Diablo Shareware
Diablo II, Diablo II Lord of Destruction
Warcraft II BNE, Warcraft III Reign of Chaos
Warcraft III The Frozen Throne
Format:

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Remarks

This message is sent to inform the server that a game should no longer be advertised to other users. It is sent when a game starts, or when a game is aborted (the host leaves).

All Battle.snp clients (DRTL, DSHR, STAR/SEXP, JSTR, SSHR, and W2BN) always send this message when logging off, even if it not in a game.

Comments
xboi209

On Diablo 2 (Open Battle.net), the client sends this packet before sending SID_LEAVEGAME.

On Diablo 2 (Closed Battle.net), this packet is never sent.

xboi209

I observed SEXP 1.16.1 sending this packet even if client has not logged in.