Helps memorize well know ports
22
21
25
110
22
21
53
25
123
53
143
443
22
80
110
23
50
67
80
69
443
80
69
123
443
143
22
25
23
143
53
123
23
143
123
443
443
67
69
161
443
23
143
123
25
443
161
67
DNS
HTTP
SSH
DHCP
POP3
SNMP
TELNET
DNS
SMTP
SNMP
TFTP
TELNET
SMTP
TELNET
DHCP
DNS
SSH
IMAP4
POP3
SMTP
SSH
FTP
HTTPS
HTTP
SNMP
NTP
DNS
POP3
POP3
IMAP
FTP
443
DNS
TFTP
IMAP4
TELNET
IMAP4
SSH
HTTP
HTTPS
SSH
SMTP
DHCP
DNS
SMTP
POP3
HTTPS
TFTP
FTP
TELNET
NTP
HTTP
Wait!
Here's an interesting quiz for you.