Networks and cyber safety: 20 revision cards

Network devices quick check for CBSE CS and IP.

Answer: B) Switch.

A switch reads the MAC address of the destination and sends data only to that device. A hub simply broadcasts data to all connected devices. A repeater regenerates weak signals, and a modem converts between digital and analog signals.

Routers, in comparison, forward data between networks using IP addresses.

IP address or MAC address, the bit counts are often mixed up.

An IPv4 address has 32 bits.

An IPv4 address has 32 bits, written as four decimal numbers from 0 to 255, like 192.168.1.10. An IPv6 address has 128 bits. A MAC address has 48 bits and is written in hexadecimal, like 00:1A:2B:3C:4D:5E.

IP addresses are logical; MAC addresses are physical.

Topology questions are regular in CBSE CS and IP networking.

Each topology has its own strengths. Bus is simple and uses less cable, but a backbone failure stops the network. Star is easy to manage, but depends on the central device. Mesh is reliable because data has alternative paths, but needs more cabling. Ring passes data around a loop, so one broken link can stop it. Tree suits large organisations.

For case-based questions, learn one advantage and one limitation of each.

Know what each device does, and the case studies become easy.

CBSE case-study questions often describe an office or school and ask which device to place where. Use a switch to connect computers within a building, a repeater when cable distance is long, and a router to connect to the internet or other networks.

A gateway connects networks that use different protocols.

A protocol is a set of rules that devices follow to communicate.

CBSE CS and IP questions often ask you to name the protocol used for a task. Web browsing uses HTTP, or HTTPS for secure connections. File uploads use FTP. Sending mail uses SMTP, while POP3 downloads mail to your device.

TCP breaks data into packets and ensures reliable delivery, and IP handles addressing and routing.

Two addresses, two different jobs.

An IP address identifies a device on a network and helps route data across networks, so it can change when you connect to a different Wi-Fi. A MAC address is built into the network interface card and identifies the hardware on a local network.

A simple way to remember: IP is like your postal address, MAC is like your fingerprint.

They look similar on a desk, but they work very differently.

Because a hub sends every packet to all devices, it wastes bandwidth and can cause more collisions. A switch forwards each packet only to the port where the destination device is connected, making the network faster and more efficient.

In CBSE case-study questions, a switch is usually the better choice for connecting computers inside a building.

A weak password is like leaving your house key under the doormat.

Strong passwords are long, hard to guess and never reused. A simple method is a passphrase: a few unrelated words joined together, which is long yet easy for you to remember. Avoid birthdays, names and phone numbers, as these are the first things someone tries.

Most importantly, turn on two-factor authentication wherever it is available. Even if a password leaks, that second step can keep your account safe.

Phishing is when someone pretends to be a trusted source to trick you into sharing passwords, OTPs or personal details.

The message may look like it is from your bank, school, a delivery company or even a friend. It often creates urgency: act now, or your account will be blocked. It may offer a prize you never applied for.

The golden rule is simple. Never share an OTP or password with anyone, and do not click unexpected links. Go to the official website or app directly instead.

Every post, comment, photo and like adds to your digital footprint, the trail of data you leave online.

Some of it is active, like what you post yourself. Some is passive, like the data websites collect as you browse. Screenshots mean even deleted content can live on.

This matters because colleges, scholarship panels and future employers may look you up. Think before posting, check your privacy settings, and be kind in comments. A good digital footprint is built one thoughtful post at a time.

Before entering a password or payment details, glance at the address bar.

HTTP sends data between your browser and a website without encryption, so it could be read if intercepted. HTTPS encrypts that connection, which protects what you send.

One important caution: HTTPS means the connection is encrypted, not that the website is honest. Scam websites can use HTTPS too. So check the exact website name carefully, and prefer typing the address yourself or using the official app.

Incognito or private browsing is useful, but it is often misunderstood.

It stops your browser from saving your history, cookies and form data on that device after you close the window. That is helpful on a shared computer.

But websites you visit, your internet provider, and your school or office network may still be able to see your activity. For real online safety, rely on good habits: strong passwords, two-factor authentication and care about what you share.

You posted something, regretted it, and hit delete. Problem solved? Not always.

Before you deleted it, others may have taken screenshots, shared it, or saved it. Some content may also remain in archives or backups.

The safest approach is to pause before posting. Ask: would I be comfortable if a teacher, a college admissions panel or my family saw this? Your digital footprint is part of your reputation, so build it thoughtfully.

Real-life cyber safety check.

Answer: (C) Refuse and end the call.

Genuine banks do not ask customers to share an OTP. An OTP is like a one-time key to your account, and anyone who has it may be able to complete a transaction or change your settings.

If you are worried, call the bank on the official number printed on your card or their official website. Share this with family members too, because these calls target everyone.

Being online every day is normal. Being safe and responsible online is a skill.

Strong passwords, two-factor authentication, spotting phishing messages and thinking before posting are habits that protect you today and your reputation tomorrow.

Digital safety and societal impacts of technology are part of CBSE Computer Science and Informatics Practices too, so these lessons help in your exams as well as in life. Share this with a friend who needs the reminder.

Take ten minutes this weekend to make your online accounts much safer.

Start by changing weak or reused passwords to long passphrases. Turn on two-factor authentication for email and social media. Check which apps have access to your accounts and remove ones you no longer use. Update your phone and apps, since updates often fix security issues. Finally, set up recovery options so you can regain access if something goes wrong.

Your email account matters most, as it can reset many others.

Combine cyber safety and Python in one small program.

The function checks three rules: at least 12 characters, at least one digit and at least one capital letter.

Answer: (A) True

'BlueRiverTrain42' is 16 characters long and has digits and capital letters, so all three rules pass. A word like 'sunflower' would return False: too short, no digit, no capital.

This is only a learning exercise; real password strength also depends on not reusing passwords and avoiding predictable words. Try adding a rule for special characters!

Children spend more time online than any generation before them. Cyber safety is now a life skill, and it is also part of CBSE Class 11 Computer Science under Society, Law and Ethics.

These conversations work best when they are calm and open, not frightening. Your child should feel they can come to you if something online feels wrong, without fear of losing their device.

Start with these simple habits at home.

Children now meet the internet long before they meet a Computer Science syllabus.

Cyber safety conversations work best when they begin early and stay open. Fear-based warnings often make children hide problems rather than share them.

Talk about passwords, privacy, unknown links and digital footprints the way you would talk about road safety, calmly and often.

Most importantly, make sure your child knows they can tell you anything without being punished for it.

A cyber safety talk you can have with your child tonight.

The safest thing to do with a password is keep it private.

Passwords should never be shared, even with close friends, and should not be easy to guess like a name or birthday.

Cyber safety is also part of CBSE Class 11 Computer Science under Society, Law and Ethics.

Children who feel safe talking to their parents are far better protected online than children who only hear warnings.

If this helped, share it with another parent in your circle.