I don’t typically suggest that people memorize a lot of things just for the sake of knowing them off the top of their head! In the real world it isn’t uncommon to use cheat sheets because there is so much to remember in tech and security. One of the few things that I recommend people put some effort into memorizing is the most commonly used ports and protocols. Here is a list of a few of those:
- Protocol – Port
- FTP – 21
- FTPS / SSH – 22
- TELNET – 23
- SMTP – 25 (Alternate: 26)
- DNS – 53
- TFTP – 69
- HTTP – 80
- KERBEROS – 88
- POP3 – 110
- NTP – 123
- NETBIOS – 137
- IMAP – 143
- SNMP – 161
- BGP – 179
- IRC – 194
- LDAP – 389
- HTTPS – 443
- SMTP SSL – 587
- MySQL – 3306
- RDP – 3389
- POSTGRESQL – 5432
Studying and memorizing some of the most commonly used ports can be extremely useful when studying for certifications. In the real world the protocol name and port number are not often mentioned together so being able to quickly understand what protocol someone is referring to when they mention a port is an essential skill.
If I missed any that you think should be added leave a comment below!