Main ports

21 FTP
22 SSH
23 Telnet
25 SMTP
53 DNS
69 TFTP (Trivial File Transfer Protocol)
80 World Wide Web standard port
88 Kerberos
123 NTP
137 Netbios/WINS (Windows Internet Name Service)
139 Netbios Windows port for null-session establishment and printer sharing
161 SNMP
389 LDAP
445 SMB
500 ISAKMP
514 SYSLOG
636 encrypted LDAP
3389 RDP (Remote Desktop Protocol)
5060 VoIP SIP (Session Initiation Protocol)
48101 used by Mirai malware to spread the infection on IoT devices