Hi Jerome,
I started out with downloading the schematics as a reference. For all components the value has been given, except for these three. Hency my question. 
In the the datasheet for the ENC28J60 there is written:
The ENC28J60 is designed to operate at 25 MHz with a crystal connected to the OSC1 and OSC2 pins. The ENC28J60 design requires the use of a parallel cut crystal.
So the requency for that one is clear, but I don’t understand what they mean with parallel cut crystal.
The datasheet for the STM is more vague about the crystal; it can be between 4 and 26 Mhz, but since I plan to use the same firmware as beeing used on the Cerb.net, I guess I need the same frequency. The crystal on the Cerb I own is marked U12.000 C01J. Does this mean that it’s 12Mhz?
Since L2 is in a 0603 package, I can’t read anything of it.
To be on the safe side, it would be great if someone from GHI could provide partnumbers or specifications for these components.
Thanks for your help so far.