leonardo ethernet pin10 in output mode

Hello,

I am working with a leonardo Ethernet board.

I tried to put pin10 in output mode with this code:

pinMode(10,OUTPUT);
digitalWrite(10,LOW);

but the pin 10 was always at HIGH level when trying to read with digitalRead.

If i remove ethernet management, by removing this line in my program, everything works fine:

EthernetClient client = server.available();

I am wondering why Ethernet library tries to do something with pin 10.
I have use both Ethernet and pin 10 in an other project, but pin 10 was in input (with pull up). Do you think i can have a problem also in input ?

Thanks

Pin 10 is the SS pin used for communication with the ethernet controller. You can't use it for something else.

Thanks
Do you know if there are some pins in the same situation i cannot use ?

Thanks

The other SPI pins are connected to the ethernet controller - though they can be used for SPI as long as you use a different chip select pin. I think that's all?