Service unknown - Port XXX
$ amap -d $ip $port
amap v5.4 (www.thc.org/thc-amap) started at 2020-09-09 23:30:39 - APPLICATION MAPPING mode
Protocol on <ip>:<port>/tcp matches ftp
Dump of identified response from <ip>:<port>/tcp (by trigger http):
0000: 3232 3020 4d69 6372 6f73 6f66 7420 4654 [ 220 Microsoft FT ]
0010: 5020 5365 7276 6963 650d 0a35 3030 2043 [ P Service..500 C ]
0020: 6f6d 6d61 6e64 206e 6f74 2075 6e64 6572 [ ommand not under ]
0030: 7374 6f6f 642e 0d0a 3530 3020 436f 6d6d [ stood...500 Comm ]
0040: 616e 6420 6e6f 7420 756e 6465 7273 746f [ and not understo ]
0050: 6f64 2e0d 0a [ od... ]