> For the complete documentation index, see [llms.txt](https://changelog.matrixemulator.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://changelog.matrixemulator.com/welcome/server/muserver/data/hack/hackpacketcheck.md).

# HackPacketCheck

<mark style="color:green;">Anti-hack validation rules for each type of packet sent by the client to the GameServer.</mark>

| Column   | Accepted values                 | Description                                                                                                                                                                                                             |
| -------- | ------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Index    | Number from 0 to 255            | The packet type (protocol opcode) this rule applies to.                                                                                                                                                                 |
| Value    | Number, or `*`                  | Specific sub-value for this packet. `*` = the rule applies to any sub-value of this packet. A specific number = the rule applies only to packets with exactly that sub-value (see notes).                               |
| Encrypt  | `0`, `1`, or `*`                | Encryption type the packet must use to be accepted. `*` = the encryption type is not checked.                                                                                                                           |
| MaxDelay | Number, in milliseconds, or `0` | Time window used to count repeated occurrences of this packet. `0` = disables repeat counting for this packet (`MinCount` and `MaxCount` are ignored).                                                                  |
| MinCount | Number, or `0`                  | Within the time window (`MaxDelay`), how many times this packet may be received before it is considered suspicious. Once this limit is exceeded, the packet is ignored (the connection remains active). `0` = disabled. |
| MaxCount | Number, or `0`                  | Higher limit within the same time window. If exceeded, the player's connection is immediately terminated. `0` = disabled.                                                                                               |

### <mark style="color:yellow;">Notes</mark>

* When an `Index` has **multiple entries with specific `Value` values** (instead of `*`), they act as a whitelist: only the listed sub-values are accepted for that `Index`. Any other unlisted sub-value is treated as an unknown packet, and the connection is immediately terminated. This is the case for packet indices `77`, `78`, and `236` in the default file, which accept only the explicitly listed sub-values.
* `MinCount` and `MaxCount` work together: exceeding `MinCount` marks the packet as suspicious and records it in the log (that packet instance is discarded), while exceeding `MaxCount` causes the player's connection to be terminated.
* In the default configuration, repeat detection (`MaxDelay`/`MinCount`/`MaxCount`) is enabled only for `Index 24`. All other packet types have these three fields set to `0`, meaning no repeat checking is performed—only the encryption check (`Encrypt`), when applicable.