Port ek logical endpoint hota hai jo computer networks mein specific services ya applications ke beech communication ko manage karta hai. Jab bhi ek computer ya device kisi network ke through data send ya receive karta hai, toh yeh data specific ports ke through route hota hai. Har port ko ek unique number assign hota hai, jise port number kehte hain.
Key Points:
1. Port Number : Port number ek 16-bit integer hota hai jo 0 se 65535 ke beech hota hai. Yeh number ek specific service ya application ko represent karta hai. Example: Web servers HTTP ke liye port 80, aur HTTPS ke liye port 443 use karte hain.
2. Well-Known Ports : Port numbers 0 se 1023 tak well-known ports kehlate hain, aur yeh specific services ke liye reserved hote hain. Jaise:
- Port 22: SSH
- Port 25: SMTP (Email)
- Port 53: DNS
- Port 80: HTTP
- Port 443: HTTPS
3. Ephemeral Ports : Port numbers 49152 se 65535 tak ephemeral ports kehlate hain, aur yeh temporary connections ke liye use hote hain. Jab ek client server se connect hota hai, toh OS in ports ka dynamic allocation karta hai.
4. Port Forwarding : Port forwarding ek technique hai jisme ek router ya firewall incoming data ko ek specific port par forward karta hai ek local network mein specific device ya service ke liye.
5. TCP vs UDP Ports : Ports TCP (Transmission Control Protocol) aur UDP (User Datagram Protocol) ke sath kaam karte hain. TCP ports reliable, connection-oriented communication ke liye use hote hain, jabki UDP ports faster, connectionless communication ke liye.
Example:
Agar aap apne browser mein `http://example.com` type karte hain, to yeh request server ke port 80 par send hoti hai (HTTP ke liye default port). Server is port par listening hota hai, aur request ko process karta hai, phir response send karta hai.
