Hi all, sorry a small correction in previous mail.. The signature that is to be matched is the following: signature gtalk_test { event "gtalk test received" payload /\x17\x03\x01/ } I tried the following signature also signature gtalk_one { event "gtalk one received" payload /.{0,0}\x17/ payload /.{1,1}\x03/ payload /.{2,2}\x01/ }