diff --git a/protocol/src/main/java/net/md_5/bungee/protocol/DefinedPacket.java b/protocol/src/main/java/net/md_5/bungee/protocol/DefinedPacket.java
index 3cc2a54a..bbb43a6d 100644
--- a/protocol/src/main/java/net/md_5/bungee/protocol/DefinedPacket.java
+++ b/protocol/src/main/java/net/md_5/bungee/protocol/DefinedPacket.java
@@ -1,6 +1,7 @@
 package net.md_5.bungee.protocol;
 
 import com.google.common.base.Charsets;
+import com.google.common.base.Preconditions;
 import io.netty.buffer.ByteBuf;
 import lombok.RequiredArgsConstructor;
 
@@ -10,7 +11,8 @@ public abstract class DefinedPacket
 
     public static void writeString(String s, ByteBuf buf)
     {
-        // TODO: Check len - use Guava?
+        Preconditions.checkArgument( s.length() <= Short.MAX_VALUE, "Cannot send string longer than Short.MAX_VALUE (got %s characters)", s.length() );
+
         byte[] b = s.getBytes( Charsets.UTF_8 );
         writeVarInt( b.length, buf );
         buf.writeBytes( b );
@@ -19,6 +21,8 @@ public abstract class DefinedPacket
     public static String readString(ByteBuf buf)
     {
         int len = readVarInt( buf );
+        Preconditions.checkArgument( len <= Short.MAX_VALUE, "Cannot receive string longer than Short.MAX_VALUE (got %s characters)", len );
+
         byte[] b = new byte[ len ];
         buf.readBytes( b );
 
@@ -27,15 +31,17 @@ public abstract class DefinedPacket
 
     public static void writeArray(byte[] b, ByteBuf buf)
     {
-        // TODO: Check len - use Guava?
+        Preconditions.checkArgument( b.length <= Short.MAX_VALUE, "Cannot send array longer than Short.MAX_VALUE (got %s bytes)", b.length );
+
         buf.writeShort( b.length );
         buf.writeBytes( b );
     }
 
     public static byte[] readArray(ByteBuf buf)
     {
-        // TODO: Check len - use Guava?
         short len = buf.readShort();
+        Preconditions.checkArgument( len <= Short.MAX_VALUE, "Cannot receive array longer than Short.MAX_VALUE (got %s bytes)", len );
+
         byte[] ret = new byte[ len ];
         buf.readBytes( ret );
         return ret;