What is a port
Find out what is a port in networking
When making network requests, you use an IP address, or a host name, and a port.
Like this:
http://localhost:8080(port 8080)ftp://127.0.0.1:29392(port 29392)
What is a port, exactly?
It’s a technique introduced to allow multiple applications to respond on the same computer, on the same protocol.
For example we might have a web server running on our machine. A second web server can be started on a different port.
Say the first runs on port 80, which is the default for web servers using the HTTP protocol. The same can run on any other port except port 80. It’s common to use port 8080 or port 81, for example.
HTTPS runs on port 443 by default.
Every protocol has a different default port, but programs are not required to use that. They can use any unused port between 1 and 65535 (16 bits unsigned = 2^16). Here is a list of default port numbers for all protocols based on TCP and UDP.
Historically:
- FTP uses 21
- Telnet uses 23
- SMTP uses 25
- POP3 uses 110
..although now for all those services you should use secure counterparts, which are based on other ports.
download all my books for free
- javascript handbook
- typescript handbook
- css handbook
- node.js handbook
- astro handbook
- html handbook
- next.js pages router handbook
- alpine.js handbook
- htmx handbook
- react handbook
- sql handbook
- git cheat sheet
- laravel handbook
- express handbook
- swift handbook
- go handbook
- php handbook
- python handbook
- cli handbook
- c handbook
subscribe to my newsletter to get them
Terms: by subscribing to the newsletter you agree the following terms and conditions and privacy policy. The aim of the newsletter is to keep you up to date about new tutorials, new book releases or courses organized by Flavio. If you wish to unsubscribe from the newsletter, you can click the unsubscribe link that's present at the bottom of each email, anytime. I will not communicate/spread/publish or otherwise give away your address. Your email address is the only personal information collected, and it's only collected for the primary purpose of keeping you informed through the newsletter. It's stored in a secure server based in the EU. You can contact Flavio by emailing [email protected]. These terms and conditions are governed by the laws in force in Italy and you unconditionally submit to the jurisdiction of the courts of Italy.