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Connecting Networks (v6)
RF and Antennas
WLAN Topologies
802.11 Frame Types
Planning Coverage with Wireless APs
Implementing Cisco Wireless Architectures
Wireless Security
Client Connectivity Troubleshooting
Secure Access
VPN
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Cisco ESA and Cisco WSA
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Theory
Module 2: Cybersecurity Threats, Vulnerabilities, and Attacks
A threat domain is considered to be an area of control, authority, or protection that attackers can exploit to gain access to a system. Cyber threats can be classified into different categories. Software attacks: DoS, computer virus Software errors: bug...
Module 3: Network Security
The cybersecurity cube: Security principles The first dimension of the cybersecurity cube identifies the goals to protect cyberspace. The foundational principles of confidentiality, integrity, and availability of data provide a focus which enables the cybe...
Key notes on Network Fundamentals
Same-layer interaction: The two computers use a protocol to communicate with the same layer on another computer. The protocol defines a header that communicates what each computer wants to do. Adjacent-layer interaction on the same computer: On a single com...
Module 1: Network Design
Reliable Networks As networks evolve, we have learned that there are 4 basic characteristics that network architects must address to meet user expectations: fault tolerance, scalability, QoS, and Security. A fault tolerant network limits the number of affect...
Module 2: Cloud and Virtualization
Cloud and Cloud Services In general, when talking about the cloud, we are talking about data centers, cloud computing, and virtualization. Data centers are usually large facilities which provide massive amounts of power, cooling and bandwidth. Only very large...
Module 3: Number Systems
Binary Number Systems Binary is a numbering system that consists of the digits 0 and 1 called bits. In contrast, the decimal numbering system consists of 10 digits consisting of the digits 0-9. Hosts, servers, and network devices use binary addressing. Specif...
Some theory on Ethernet straight-through and crossover cabling for 10BASE-T, 100BASE-TX and 1000BASE-T
A general introduction on Ethernet straight-through and crossover cables In an Ethernet straight-through cable, pins on one end correspond exactly to the corresponding pins on the other end (pin 1 to pin 1, pin 2 to pin 2, etc.). Using the same wiring schem...
Auto MDI-X a prueba: cables straight-through, crossover, hubs, switch y PCs
En este artículo pongo a prueba la teoría sobre los cables de Ethernet straight-through y crossover, como se muestra en el artículo sobre este tema.Para esta práctica usaré lo siguiente: Cable Cat6a usando solo los pares 2 y 3 con un pinout T568A en ambos e...
Autonegotiation and duplex mismatch theory
Introduction to autonegotiation For any 10/100 or 10/100/1000 interfaces (that is, interfaces that can run at different speeds), Cisco Catalyst switches default to a setting of duplex auto and speed auto. As a result, those interfaces attempt to automatically...
Instalación de Windows 98
En primer lugar, tener en cuenta que hay que desconectar fisicamente el segundo disco duro. Si el PC tiene dos discos duros, el primero tendrá la letra C y el segundo la D.Al insertar el disquete de inicio (unidad A:) y seleccionar la instalación con CD-ROM,...
Paso 1: Backup de BBDD y otros archivos de configuración
El primer paso para la migración de Bookstack instalado en una Raspberry Pi con Ubuntu 22.04 a otra con Raspberry Pi OS Lite (32-bit) basado en Debian 12 bookworm, es hacer backup en la actual de lo siguiente: BBDD Usar el siguiente comando: sudo mysqldump ...
Paso 2: Instalación de Raspbian y paso de los archivos de backup
Por el modelo de Raspberry (3 B+), se instala Raspberry Pi OS Lite (32-bit): A fecha 26/12/2023, esta es la versión más reciente Instalar con Raspberry Pi Imager, editando las opciones antes de instalar. Ojo, escribir siempre la password antes de instalar: ...
Paso 3: Instalación limpia de Bookstack
En este punto se hace una instalación limpia de Bookstack. Para ello se hace uso del script que tiene Dan Brown en la guía de instalación para Ubuntu 22.04 pero algo modificado: Script modificado en mi GitHub Las modificaciones son las siguientes: Cambio en...
Paso 4: Restore de BBDD y el resto de archivos + consideraciones para dejarlo todo como estaba
Empezamos con el restore de la BBDD: sudo mysql -u root bookstack < bookstack.backup.sql Después de esto, ir a /var/www/bookstack y ejecutar php artisan migrate como se indica en los docs. por si acaso. Lo normal es que diga que no hay nada que migrar. Co...
Anexo: Fuentes
Installing BookStack on Debian 12 (Bookworm) with HTTPShttps://www.youtube.com/watch?v=UpwfeFmzxLk missing images #4146https://github.com/BookStackApp/BookStack/issues/4146#issuecomment-1493497503 Install and Configure Sambahttps://ubuntu.com/tutorials/insta...
Instalación de drivers + otras cosas útiles
Al cargar por primera vez con un mouse conectado por USB, dejar que seleccione el driver por defecto (dispositivo HID) y continuar. Lo mismo con el monitor, seleccionar el driver por defecto Monitor PnP genérico Dado que no hay un driver para dispositivos ...
Reverse telnet theory + practical example
When a user telnets to a router, he is “logged on” directly to the router. Cisco adds a special twist: if you telnet to a special port on the router, the router redirects the incoming telnet connection back out a selected asynchronous line, rather than interna...
How to make an RJ45 to RJ45 rollover cable
A rollover cable (also known as a Yost cable, Cisco cable, or a Console cable) is a type of null-modem cable that is used to connect a computer terminal to a router's console port. This cable is typically flat (and has a light blue color) to help distinguish i...
US Robotics 56K Faxmodem installation on Windows 98 (drivers + ControlCenter)
Shut down your computer and connect the serial modem cable to the modem and the computer. Plug in the modem's power supply and turn on Windows 98 When the following screen appears (which happens when the modem is detected by Plu...
Anexo - Consideraciones
31/12/2023: Al quitar el modo bridge del HGU y usarlo de nuevo como router por defecto (reset de fabrica incluido), la Raspberry ha cogido una IPv6 del server DHCP del router y cuando intenta resolver a sergio-jimenez.net lo hace mediante IPv6 por defecto. L...