>>>>> "Daniele" == Daniele Venzano <venza@libero.it> writes: Daniele> I'm now quite sure that my ISP is blocking incoming packets Daniele> with protocol 41, it seems strange to me, but no other Daniele> explanation comes to my mind... I had that problem when I first tried setting up a 6in4 tunnel several years ago. It turned out not to be the ISP I was colo'ed with but rather the tier1 between my ISP and the other endpoint. -JimC