I think I found the problem. I think it misbehaved because of an illegal character in the "HOSTNAME". Changed the hostname yesterday and It was still alive this morning even if I have not pinged it.

@gohan said in Arduino Pro Mini Shield for RFM69(H)W: If I remeber right that pin is used as input so the RFM69 is not receiving any 5v signal. In addition there are people claming they have the RFM69 module working on 5v on data pins and 3.3v on vcc, but I hardly suggest to do it. thank you just what i thought . about direct 5v on data...well... i seen a big red sign saying n :DONT do it! lol Level converters are so cheap...that i ordered 5 or 10 thoguether with rfm69 board. sorry about hijack this topic, i though i was on general discussion