FTP
Nmap discovered a FTP server on the target port 21
The running service appears to be ProFTPD
Null Session
┌──(kali㉿kali)-[~/archive/htb/labs/sightless]
└─$ ftp $IP
Connected to 10.129.206.178.
220 ProFTPD Server (sightless.htb FTP Server) [::ffff:10.129.206.178]
Name (10.129.206.178:kali): ftp
550 SSL/TLS required on the control channel
ftp: Login failed
ftp> It would appear that the target FTP instance is configured with SSL