File Transfer Protocol (FTP)
Secure Shell (SSH)
22
TCP
Simple Mail Transfer Protocol (SMTP)
25
TCP
TACACS+
49
TCP
Domain Name System (DNS)
53
UDP
Dynamic Host Configuration Protocol (DHCP)
67/68
UDP
Kerberos
88
UDP/TCP
Post Office Protocol (POP)
110
TCP
Network Time Protocol
123
UDP
Server Message Block (SMB)
139
UDP
Internet Message Access Protocol (IMAP)
143, 993
TCP
Simple Network Management Protocol (SNMP)
161/ 162
UDP
Lightweight Directory Access Protocol (LDAP)
389
UDP
Secure Socket Tunneling Protocol (SSTP)