Stereoayapa

IP Addressing + DHCP Made EASY! Every Network Engineer MUST understand these basics before moving to advanced networking concepts! 🔹 In this guide you’ll learn: ✅ Class A, B & C IP Addresses ✅ Private IP Ranges (RFC1918) ✅ DHCP vs Static IP ✅ APIPA Address Explained ✅ Subnet Mask Basics ✅ Real-world device examples 🔸 Quick Reminder: 🔹 DHCP = Automatic IP Assignment 🔹 Static IP = Manual & Fixed Address 🔹 APIPA (169.254.x.x) appears when DHCP fails 👉 Interview Question: Why are servers usually configured with Static IP addresses instead of DHCP? 📚 Perfect for CCNA, CCNP & IT Beginners 💾 Save this for interview preparation 🔁 Share with networking students

@CyberRacheal C

Networking Question 👇🏽. Give it a try. How many usable host addresses are available in a network with the subnet mask /26? A) 30 B) 32 C) 62 D) 64

@CyberRacheal NAT

Which technology allows multiple devices on a local network to share a single public IP address for internet access? A. DHCP B. NAT C. DNS D. ICMP

It's 2026, and you're still using plaintext DNS, which anyone on your network can read and alter?  It's high time you protect and sneak in your DNS queries under HTTPs encryption, protecting your queries from bad actors! 🔒

@CyberRacheal C

Which of the following is a public IP address? A. 10.255.255.254 B. 192.168.50.50 C. 172.15.1.1 D. 172.16.0.1

En cualquier ferretería de América Latina se vende una droga legal. Cuesta menos que un almuerzo, no necesita receta y puede provocar muerte súbita en la primera inhalada. En "Cómo te Afecta" hablamos del consumo de pegamentos, solventes, aerosoles y poppers en América Latina.

@CyberRacheal B

What is the default subnet mask for a Class B IP address? A. 255.0.0.0 B. 255.255.0.0 C. 255.255.255.0 D. 255.255.255.255

@cyber_rekk A& B

A network engineer configures a /31 subnet on a point-to-point link. Which statements are correct? Options: A. Both IP addresses in the subnet are usable host addresses B. The subnet has no broadcast address C. The subnet is invalid in IPv4 D. The subnet wastes IP addresses

@CyberRacheal C

Which of the following is a Layer 2 (Data Link)protocol? A. IP (Internet Protocol) B. TCP (Transmission Control Protocol) C. ARP (Address Resolution Protocol) D. HTTP (Hypertext Transfer Protocol

HOW TO RETRIEVE A FORGOTTEN PASSWORD ON UBUNTU Firstly this is not a backdoor. It’s a password recovery method for physical access only. If you’re trying to break into a computer you don’t own – stop. That’s illegal. If it’s your machine but you forgot the password, this works. If the disk is encrypted, you’re likely out of luck. Step 1: Determine if disk encryption is enabled. Did you check “Encrypt disk” during install? If yes, recovery is nearly impossible without the passphrase. This method will fail. If no, proceed. Step 2: Reboot and access GRUB. Restart your computer. When the boot menu (GRUB) appears – usually right after the manufacturer logo – press and hold Shift (BIOS) or spam Esc (UEFI). If you miss it, reboot and try again. Step 3: Enter recovery mode. In GRUB, highlight the line that says “Advanced options for Ubuntu.” Under it, select a kernel ending with “(recovery mode).” Press Enter. Step 4: Drop to a root shell. You’ll see a menu with options like “resume,” “clean,” “dpkg,” “root.” Use arrow keys and select “root” – “Drop to root shell prompt.” Press Enter. It will say “Press Enter for maintenance.” Do that. Step 5: Remount filesystem as read-write. By default, recovery mode mounts the filesystem as read-only. Run this exact command: ``` mount -o remount,rw / ``` If you get an error, try: ``` mount -rw -o remount / ``` Step 6: Reset the password. Use this command – replace username with your actual username (if you don’t remember it, use ls /home to see user folder names): ``` passwd username ``` You’ll be prompted to type a new password twice. Nothing shows on screen – that’s normal. Step 7: Reboot normally. Type: ``` reboot ``` Or press Ctrl+Alt+Del. Boot into Ubuntu normally. Login with your new password. Protect yourself absolutely. · Do not skip the remount step – you’ll get a “read-only filesystem” error. · If passwd says “Authentication token lock busy,” run mount -o remount,rw / again carefully. · If you have multiple users or encrypted home folders (ecryptfs), resetting the password may not unlock your data – you’ll need your original encryption passphrase. If this doesn’t work: · GRUB missing? Boot from a Ubuntu live USB, mount your hard drive, and chroot into it – advanced but possible. · Full disk encryption? Unless you remember the LUKS passphrase and just forgot your user password, your data is gone. That’s the point of encryption. · Do not try “password recovery” tools from random websites. Most are scams or malware. Final and most important step: Prevent this from happening again. Write down your password and store it somewhere physically safe. Use a password manager. Or – better security – enable automatic login only for low-risk personal machines. For truly important data, use a YubiKey or SSH key instead of a password you can forget. This is educational. Perform only on your own hardware. Proceed with caution, or better yet – keep a written backup of your password.

@CyberRacheal B

A network uses the subnet 192.168.50.0/28. How many usable host addresses are available in this subnet? A. 6 B. 14 C. 16 D. 30

I think it’s finally time to get your CCNA. And I want to help. Starting in May, we are opening up our CCNA course to those who are serious…..for FREE. It will be a focused CCNA journey from May to August. Me and @CioaraJeremy will be helping you along the way with livestreams and community. No more excuses. It’s time to get serious. Join here: ntck-ac.co/ccnasummerearl… This is going to be the summer that you get your CCNA. #SummerOfCCNA

🚨Conoce la presión normal por edad

@CyberRacheal C

Which command-line tool is used to show the path a packet takes to reach a destination? A. Ipconfig B. Ping C. Traceroute D. Netstat

Un día como hoy, 12 de abril, en la #HistoriaDeHonduras 📷 1797. Arriban al puerto Port Royal, en Roatán, 2,026 caribes o garífunas, después de haber sido expulsados por orden del Rey inglés Jorge III de la isla de San Vicente. El 5 de febrero, el Secretario de Relaciones Exteriores del Imperio inglés ordenó al Almirante Henry Harvey la expulsión de este grupo étnico y que los llevara a la Bahía de Honduras (región que incluye territorios de la actual Guatemala, Belice y Nicaragua). Al llegar a la isla de Roatán en la actual Honduras, Jack, el segundo al mando de los caribes, afirmó ante la autoridad colonial de la Provincia de Honduras: "Yo no mando en nombre de nadie: yo no soy inglés, ni francés, ni español, ni QUIERO SER NADA DE ESTO: soy CARIBE SIN SUJECIÓN, no quiero ser más, ni quiero tener más". La presencia africana en Honduras data desde 1524, pero los garífunas llegan 270 años después, en 1797. Actualmente, son una de las culturas vivas más importantes del país. Comparto un frangmento de un documental de 1950

@CyberRacheal NAT

Which technology allows multiple devices on a local network to share a single public IP address for internet access? A. DHCP B. NAT C. DNS D. ICMP

Before DNS, the Internet ran on a single text file. You wanted a hostname? You emailed Elizabeth Feinler’s team at SRI. They edited their local HOSTS.TXT and then everyone downloaded the new copy! That worked… until it didn’t. By 1983, it was obvious this wouldn’t scale, so Paul Mockapetris created DNS: distributed, hierarchical, no single point of failure. The modern Internet exists because we stopped relying on one file to keep it all straight!

@CyberRacheal A

If there is no time constraint, which protocol should be employed to establish a reliable connection between two devices? A. TCP B. SNMP C. UDP D. DHCP

🚨ATENCIÓN 🚨 Si hoy te hackearan una cuenta, ¿sabes exactamente qué hacer? Abrimos hilo con las acciones concretas que debes realizar en los primeros 15 minutos. Actuar rápido y de manera correcta puede evitar la pérdida de dinero y/o información.

@cyb3rshi3ld B

🔐 In Identity Management, which component controls user access to resources within a network? A) Authentication B) Authorization C) Accounting D) Encryption #Cybersecurity #IdentityManagement #EdTech