出自Gnutella封包特徵碼的一段話:"The first part matches UDP messages - All start with "GND", then have a flag byte which is either \x00, \x01 or \x02, then two sequence bytes that can be anything, then a fragment number, which must start at 1."。Foxy實際運行的一段封包:"47 4e 44 02 00 07 01 …",前三欄位47 4e 44為"GND"的十六進位表示法,第四欄位以後之特徵皆符合Gnutella之特徵碼規範。