DNS (name queries)
UDP 53
DNS (zone transfers)
TCP 53
RADIUS
UDP 1812/1813
UDP 1645/1646
TACACS+
TCP 49
SNMP
UDP 161
LDAP
TCP 389
SIP
TCP 5060/5061
RTP
TCP 5004/5005
H.323
TCP 1720
RDP
TCP 3389
UDP 3389
MGCP
TCP 2427/2727
UDP 2427/2727
SSH
TCP 22
Well-known ports
0-1023
Ephemeral ports
1024-5000
Dynamic/private ports
49152-65535
Registered ports
1024-49151
Kerberos
TCP 88
UDP 88
SCP (uses SSH)
TCP 22
SFTP (uses SSH)
TCP 22
SMTP (SSL/TLS)
TCP 465
IPSec (VPN with IKE)
UDP 500
LDAP (SSL/TLS)
TCP 636
IMAP (SSL/TLS)
TCP 993
POP (SSL/TLS)
TCP 995
L2TP
UDP 1701
PPTP
TCP 1723
MS SQL Server
TCP 1433
SNMP Trap
UDP 162
DHCP
UDP 67/68
SNTP/NTP
UDP 123
TFTP
UDP 69
HTTP
TCP 80
HTTPS/SSL
TCP 443
NNTP
TCP 119
Telnet
TCP 23
SMTP
TCP 25
POP3
TCP 110
IMAP4
TCP 143
FTP active port (data mode)
TCP 20
FTP control port
TCP 21
NetBIOS
TCP/UDP 137
TCP 139
UDP 138
SMB
TCP 445