Regarding https://bitcointalk.org/index.php?topic=28022.0
main.cpp has: "char pchMessageStart[4] = { 0xf9, 0xbe, 0xb4, 0xd9 };" Per discussion on the thread linked, leaving the signedness of pchMessageStart is unsafe for values > 0x80. This patch specifies 'unsigned char' in main.cpp and net.h.