---
title: "Intranet vs Internet and intranet protocols"
subject: "Internet and Intranet"
chapter: 1
key: "semester_8/internet_and_intranet:intranet-vs-internet-protocols"
source: https://www.bctengineer.com/q/semester_8/internet_and_intranet/intranet-vs-internet-protocols
site: BCT Engineering
---

# Intranet vs Internet and intranet protocols

Internet and Intranet · Chapter 1: Introduction

- Asked in: 2069 Bhadra (old course), 10 marks
- Video: [Difference between Internet, Intranet and Extranet](https://www.youtube.com/watch?v=HEzN3B_aXE4) — Waqas Tech Videos
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/internet_and_intranet/intranet-vs-internet-protocols
- Whole chapter: https://www.bctengineer.com/md/semester_8/internet_and_intranet/chapter-1

## Question

What is the difference between intranet and internet? Explain the widely used protocols in intranet.

## Short answer

Intranet restricts access to internal authorized users with private IPs; Internet is a global public network. Key intranet protocols are TCP/IP for transport, HTTP/HTTPS for web, DNS/DHCP for naming and addressing, LDAP for authentication, SMB/NFS for file sharing, and SMTP/IMAP for email.

## Answer

#### Difference between intranet and internet

| Basis | Intranet | Internet |
|---|---|---|
| Definition | Private network of an organisation using Internet technology | Global public network of networks |
| Access | Only authorised users | Anyone with a connection |
| Ownership | One organisation | No single owner |
| Security | Firewall, controlled access | Open, higher risk |
| Scope | One organisation, LAN/WAN | Worldwide |
| Content | Internal documents, applications | Public content and services |
| Addressing | Private IP addresses | Public IP addresses |
| Cost and control | Organisation manages and pays | Shared; ISP charges |

#### Widely used protocols in an intranet

An intranet uses the same TCP/IP suite as the Internet.

1. **TCP/IP (IP, TCP, UDP):** basic addressing, routing and reliable/unreliable delivery.
2. **HTTP/HTTPS:** access to internal web pages and web applications through browsers (ports 80/443).
3. **FTP/SFTP:** file transfer between clients and file servers (ports 21/22).
4. **SMTP, POP3, IMAP:** sending and receiving internal e-mail (ports 25, 110, 143).
5. **DNS:** resolves internal host names to IP addresses (port 53).
6. **DHCP:** assigns IP address, mask, gateway and DNS server automatically to clients (ports 67/68).
7. **LDAP/Active Directory, Kerberos:** central user authentication and directory services.
8. **SMB/CIFS, NFS:** file and printer sharing.
9. **Telnet/SSH:** remote login and administration (SSH is secure).
10. **SNMP:** monitor and manage network devices.
11. **NTP:** time synchronisation.
12. **IPsec/VPN protocols:** secure remote access for staff from outside.
13. **SIP/RTP:** internal VoIP and video conferencing.
14. **ARP, ICMP:** address resolution and diagnostics such as ping.
15. **Routing protocols (RIP, OSPF):** exchange routes between internal subnets.


#### Typical use in a small organisation (example)

An employee opens the intranet portal at `http://intranet.company.local`. DHCP gave the PC its address; DNS resolves the portal name; HTTP fetches the page from the internal web server; LDAP checks the login; SMB maps the shared drive; SMTP/IMAP handle internal mail; the firewall allows only HTTP/HTTPS, DNS and mail out to the Internet. This shows that the same protocols as on the Internet are used, but inside a controlled boundary.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which addressing difference applies to intranet vs Internet?
   A. Intranet uses public IPs; Internet uses private IPs
   B. Both use only private IPs
   C. Intranet uses private IP addresses; Internet uses public IP addresses
   D. Neither uses IP
   Answer: C. Intranets use private ranges (10.x, 172.16-31.x, 192.168.x) behind a firewall; the Internet uses public addresses. (Key point: Intranet vs Internet addressing)

2. What does DHCP do in an intranet?
   A. Resolves names to IPs
   B. Synchronises time
   C. Authenticates users
   D. Automatically assigns IP address, mask, gateway and DNS server to clients
   Answer: D. DHCP (ports 67/68) configures clients automatically. (Key point: DHCP role)

3. Which protocol is the secure option for remote administration?
   A. Telnet
   B. SSH
   C. FTP
   D. SNMP
   Answer: B. SSH encrypts remote login; Telnet is not secure. (Key point: Secure remote login)

4. In the intranet portal example, which protocol checks the user's login?
   A. LDAP (directory authentication)
   B. SMB
   C. SMTP
   D. NTP
   Answer: A. LDAP/Active Directory provides central authentication; DNS resolves the name, HTTP fetches the page, SMB maps drives. (Key point: Protocols in a portal visit)

## Related in Internet and Intranet

- [Internet vs Intranet and DNS need](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Ainternet-intranet-compare-dns) — Internet and Intranet, chapter 1
- [Intranet vs Internet, firewall, content filtering](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Aintranet-internet-benefits-firewall) — Internet and Intranet, chapter 1
- [Intranet, Internet, Extranet comparison and resources](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Aintranet-internet-extranet-compare) — Internet and Intranet, chapter 1
- [Web-mail to POP3 message transfer protocols](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Aalice-bob-email-protocols) — Internet and Intranet, chapter 3
- [Email security with diagram and protocols](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Aemail-security-diagram) — Internet and Intranet, chapter 3
- [Intranet implementation procedure and VPN](https://www.bctengineer.com/question.md?key=semester_8%2Finternet_and_intranet%3Aintranet-implementation-procedure-vpn) — Internet and Intranet, chapter 6

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- [Short note: Internet / Intranet](https://www.bctengineer.com/question.md?key=semester_2%2Fbasic_electronics_engineering%3Ashort-note-internet-intranet) — Basic Electronics Engineering, chapter 5
- [Why bricks are widely used](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Awhy-bricks-widely-used) — Civil Engineering Materials, chapter 3, asked 3×
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