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**TCP and UDP use the same port range: from 0 to 65535.**
The difference between TCP and UDP is that **they have different port spaces**.

In short:
**TCP port 80 and UDP port 80 are different ports**.

---

## Overall port range

- **Minimum:** 0
- **Maximum:** 65535
- Total: **65,536 ports** for TCP and the same number for UDP

---

## Main port ranges

### 1. **Well-known ports (0-1023)**

Standard, "well-known" ports.

Used by basic network services:

- 80 - HTTP
- 443 - HTTPS
- 22 - SSH
- 25 - SMTP
- 53 - DNS

Usually:

- require administrator privileges
- used by servers

---

### 2. **Registered ports (1024-49151)**

Ports assigned to specific applications.

- used by servers and services
- not considered system ports

Examples:

- 3306 - MySQL
- 5432 - PostgreSQL
- 8080 - alternative HTTP

---

### 3. **Dynamic / Ephemeral ports (49152-65535)**

Temporary (dynamic) ports.

Used by:

- client applications
- assigned automatically by the OS
- exist only for the duration of the connection

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## Important points for the interview

- the ranges are **the same for TCP and UDP**
- the port spaces are **separate**
- a port is part of an **end-to-end connection**
- a connection is uniquely identified by the set:

```
  source IP + source port +
  destination IP + destination port +
  protocol (TCP/UDP)
  ```

---

## In short, for the interview

> **The range of TCP and UDP ports is 0 to 65535. It is divided into well-known (0-1023), registered (1024-49151), and dynamic/ephemeral (49152-65535); TCP and UDP have independent port spaces.**

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