There are different kinds of DHL tracking numbers, in this passage, I will make a summarize about DHL tracking numbers.
1. 10-digit tracking number, eg:1884151334 . This is quite common, some people even think this is the only form of DHL. But actually it is not. You can track it on the official site of Global DHL : www.dhl.com or www.trackingmore.com
2. 12-digit tracking number, eg: 436968244236 . This is a package transit from Germany to China and carried by Deutsche Post DHL.
In order to track this kinds of package, you need enter the official site of Deutsche Post DHL : www.dhl.de. Also you can try trackingmore.
3. 9 digit with 4 letters, eg: CK024508132DE. This is an UPU( Universal Postal Union ) number. If your package is carried by Deutsche Post DHL, then after your package arrived the destination country such as China, an exchange number will come out, and you can track it on the official site of the local courier website such as China EMS.
4. 20-digit tracking number, eg: 00340433836093401261. This is a warehouse number, you can track it in www.dhl.de.
Note: Global DHL is different from Deutsche Post DHL, these are two different websites and different tracking systems. But you can always track your packages on www.trackingmore.com.