Networking is a marvel of interconnected devices and languages – part of that inter connectivity is allowing devices to talk to one another without getting any crosstalk or confusion this is done by separating network traffic into ports – allowing traffic to be managed easier and allows for overall greater security.

HTTP (Hypertext Transfer Protocol)
HTTP uses port 80 – this is usually used for web traffic – for webpages.
HTTPS (Hypertext Transfer Protocol SSL)
Similar to port 80 although this is using port 443 – this is used for secure and encrypted traffic and used for website logon pages and secure VPN connections.
FTP (File Transfer Protocol)
Using port 20 and 21 – this is used for FTP traffic to and from.. used to upload webpages and files and folders from one host to another .
POP (Post Office Protocol) – Also POP3
POP and POP3 uses the port 110 – this provides the ability to receive emails – commonly used by ISPs email service.
SMTP (Simple Mail Transfer Protocol)
SMTP uses the port 25 – this provides the ability to send emails – commonly used by ISPs email service.
IMAP
Uses TCP and UDP port 143 – IMAP is another email service that is commonly used by email providers that hold emails on their servers – instead of downloading them to the local computer.
Telnet
Telnet uses port 23 – and is commonly used for remote administration of devices using a command line.