the presurfer style

Some websites links to help to cure your boredom

noreply@blogger.com (fenix) — Tue, 07 Oct 2025 21:51:00 +0000

Forget the endless scrolling through social media or the same old video platforms

Forget the endless scrolling through social media and rediscover the internet’s weird, wonderful side. This list is your ultimate boredom-killer — packed with creative, relaxing, and downright bizarre websites that remind us how fun the web can be. From exploring virtual planets to slapping eels, feeding digital cats, or traveling through random windows across the world — here are the best useless but brilliant sites to brighten your day

Rediscover the Web: 30+ Fun & Weird Websites to Cure Boredom

Forget endless social feeds. This curated list gathers the web’s most delightful, strange, and relaxing corners — tiny experiments, odd games, and serene escapes that are perfect when you want something different. Click, explore, and enjoy.

Pointer Pointer — pointerpointer.com
Shows a random photo of someone pointing exactly at your cursor. Surprisingly hypnotic and hilarious.
This Is Sand — thisissand.com
Turn your screen into a meditative sand art canvas. Create soothing landscapes with falling colored grains.
Zoomquilt — zoomquilt.org
Dive into an infinite, seamless painting that zooms forever — a trippy, dreamlike experience.
YouTube Time Machine — https://timemachinevideos.com/
Travel back in time through YouTube videos from specific years. Relive nostalgia instantly.
Radiooooo — radiooooo.com
A time-travel radio: choose a country and decade to hear what people were listening to back then.
Neal.fun — neal.fun
A collection of mini-games and creative experiments by Neal Agarwal. Each one is charmingly unique.
Drive & Listen — driveandlisten.herokuapp.com
Virtually drive through cities around the world while listening to live local radio.
Surprise Me Button — surprisemebutton.com
Press it and discover a random, entertaining site — just like magic.
Little Alchemy 2 — littlealchemy2.com
Combine basic elements to create new items — from fire to unicorns. Addictive and clever.
A Soft Murmur — asoftmurmur.com
Mix ambient sounds like rain, wind, or coffee shop noise to create your perfect background.
GeoGuessr (Free) — geoguessr.com/free
Guess where you are in the world based on Google Street View. Travel and learn geography in a fun way.
EelSlap — eelslap.com
Move your cursor to slap a man with an eel in slow motion. Pointless perfection.
Find the Invisible Cow — findtheinvisiblecow.com
Use audio clues to locate an invisible cow on your screen. Silly but hilarious.
Penga (vole.wtf/penga) — vole.wtf/penga
A cute and chaotic penguin-flinging game. Launch penguins and watch the fun.
PopCat.Click — popcat.click
Click to make a cat “meow” and compete globally for clicks. Internet absurdity at its finest.
Bongo.cat — bongo.cat
Make music by tapping your keyboard as a cartoon cat plays bongos. Pure joy.
WindowSwap — window-swap.com
Look out of someone else’s window somewhere in the world. Serene and strangely human.
HackerTyper.com — hackertyper.com
Pretend you’re a hacker by smashing random keys. Instant “tech genius” vibes.
MapCrunch.com — mapcrunch.com
Teleport to a random place in the world via Street View. Discover new locations instantly.
Stellarium-Web.org — stellarium-web.org
Explore a real-time interactive night sky with constellations and planets.
Stars (Chrome Experiments) — stars.chromeexperiments.com
A 3D universe visualization built by Google Chrome Experiments. Mesmerizing.
Spend Bill Gates’ Money — neal.fun/spend
Try to spend all of Bill Gates’ fortune on crazy things. Harder than it sounds!
Space Elevator — neal.fun/space-elevator
Climb a virtual elevator into space with facts as you ascend. A cool cosmic journey.
Trashloop.com — trashloop.com
Watch endlessly looping aesthetic videos of trash and texture — oddly satisfying.
PetPet Generator (BenIsland) — benisland.neocities.org/petpet/
Add the classic “pet pet” animation to any image or meme. Internet nostalgia.
2020game.io — 2020game.io
A side-scrolling indie game recreating the chaos of the year 2020. Simple but fun.
Lifeclock.be — lifeclock.be
A site that visualizes your life in weeks. Deeply existential but fascinating.
ListChallenges.com — listchallenges.com
Browse and check off themed lists (movies, food, travel). Surprisingly addictive.
RainyMood.com — rainymood.com
Listen to realistic rain sounds for focus or sleep. Classic and calming.
Noot.Space — noot.space
Random memes, odd animations, and endless penguin noises. Perfectly nonsensical.
Iceberger Simulator — joshdata.me/iceberger.html
Tilt and float an iceberg in water physics simulation. Surprisingly relaxing.
SlapKirk.com — slapkirk.com
Slap Captain Kirk from Star Trek endlessly. Weirdly satisfying.
TypeTheAlphabet.App — typethealphabet.app
See how fast you can type the alphabet. Simple yet oddly competitive.
PixelSpace Solar System — joshworth.com/dev/pixelspace/pixelspace_solarsystem.html
Zoom out from Earth through a pixel-scaled solar system. Mind-blowing perspective.
Star Wars Intro Creator — starwarsintrocreator.kassellabs.io
Create your own Star Wars opening crawl with music and text.
How Many People Are In Space Right Now? — howmanypeopleareinspacerightnow.com
See how many astronauts are currently orbiting Earth.

The Mystery of Beethoven's Metronome

noreply@blogger.com (fenix) — Wed, 06 Jan 2021 01:30:00 +0000

The Mystery of Beethoven's Metronome. New research says it's possible that the composer suffered from early adopter syndrome.

The Medium - Official 14-Minute Gameplay

noreply@blogger.com (fenix) — Wed, 06 Jan 2021 01:24:00 +0000

Take an extended look at the gameplay of The Medium, a one of its kind horror game where you can play in the real world and the spirit world at the same time. Travel to an abandoned and haunted hotel resort to discover a mystery only a medium can solve.

History of Swear Words | Official Trailer | Netflix

noreply@blogger.com (fenix) — Wed, 06 Jan 2021 01:22:00 +0000

Garuda Linux Review: You'll be Blown Away by its Looks [New Distro based on Arch]

noreply@blogger.com (fenix) — Wed, 06 Jan 2021 01:20:00 +0000

Solar Orbiter flyby of Venus

noreply@blogger.com (fenix) — Wed, 06 Jan 2021 01:17:00 +0000

How to Use TCP/IP Tools to Troubleshoot a Connection from command line in windows 10

noreply@blogger.com (fenix) — Thu, 30 Jan 2020 01:35:00 +0000

How to Use TCP/IP Tools to Troubleshoot a Connection

Windows 10 provides a number of TCP/IP tools for troubleshooting network Connectivity problems. You should be familiar with the following tools:

Ping
Ipconfig
Net View
Tracert
Pathping

Ping

When the problem appears to be with TCP/IP, start the troubleshooting process with the Ping command, Which allows you to check for connectivity between devices on a network.

When you use the Ping command, you ping from the inside out. You want to Find out where the communication and connection fail. For example, you ping the loopback address first. then a local computer on the same network, then a DNS or DHCP server on the local subnet if one exists. then the default gateway, then a remote computer on another network, and finally a resource on the Internet. You should be able to Find out where the breakdown occurs by compiling the results of these checks.

When using the Ping command, you can use either the computer name or the computer's IP address.

Pinging the Loopback Address The loopback address (127.0.0.1) is the first thing YOU should check when a TCP/IP problem appears. If this check fails, the TCP/IP configuration for the local machine is not correct. To ping the loopback address, follow these steps:

1. Press Windows+R to open “Run” dialog box. Type “cmd” and then click OK

2. Type ping 127.0.0.1. A successful ping to a loopback address is shown in the next pic

If pinging the loopback address fails, check the configuration of TCP/IP by following these steps:

1.Open the Network Connections window, Press the Windows + R key at the same time to open the Run box. Type ncpa.cpl,right click the configured connection and choose properties

2 Select Internet Protocol (TCP/IP), and click Properties to view the configuration u a static address is configured and a DHCP server is available, select Obtain An IP Address Automatically. 1f Obtain An IP Address Automatically is selected butt static IP address is necessary, select Use The Following IP Address; then enter the address, subnet mask, and gateway to use. If the configuration is correct, you might have to reset TCP/ 1P.

3.Click OK in the Properties dialog box and OK in the connection’s Properties dialog box. Reboot the computer if prompted.

Pinging Other Resources To ping any other computer on the network, simply replace the loopback address with the TCP/IP address of the resource on the network. Ping a local computer on the same subnet first, and then ping the gateway address. If you Can ping the loopback address (a local computer on the same subnet), but the Ping command to the gateway fails, you probably found the problem. In this case, check the configuration on the local computer for the gateway address and verify that the gateway (or router) is operational.

If the ping to the gateway address is successful, continue to ping outward until you find the problem. For instance, ping a computer on a remote subnet and verify that the DNS server is operational.

Although pinging remote computers is a useful troubleshooting technique. many hosts and routers filter out incoming internet Control Message Protocol (ICMP) echo requests (which are the basis of ping). Such hosts do not respond to a ping request, making it appear that the host cannot be reached. By default, computers protected with Windows Firewall also filter out such requests to protect the computers from intruders that would use lCMP~based denial of service (DoS) attacks or use ICMP to map a remote network.

Using Ipconfigin Windows 10 from command prompt

You can use the Ipcontig cormnand-line utility to view current TCP/IP configuration information for a computer. To use Ipconfig, open the command prompt window and type Ipconfig to view basic TCP/IP parameters, Ipconfig /all to view the complete TCP IP configuration

Note You must run lpconfig from a command prompt. If you try to execute it by using the Run command on the Start menu, the command window will close before you have a chance to read the information that is displayed.

Additional Ipconfig options include the following:

/release Releases DHCP-supplied configuration information
/renew Renews DHCP-supplied configuration information
/flushdns Purges the local DNS cache (the area of memory that stores recently resolved names so that the client does not have to contact the DNS server each time)
/registerdns Renews DHCP-supplied configuration information and registers the DNS name to IP address information with DNS
/displaydns Displays the contents of the local DNS cache
/setclassid Provides for the configuration of DHCP user classes, which can control the way IP addresses are assigned

Using Net View

The Net View command is another command that you can use to test TCP/IP connections. To use the command, log on with the proper credentials that are required to view shares on a remote or local computer, open a command prompt, and type net view\\ComputerName or net view \IPAddress. The resulting report lists the file. and print shares on the computer. If there are no file or print shares on the computer you see the message There Are No Entries In The List.

If the Net View command fails, check the following:

The computer name in the System Properties dialog box
The gateway or router address in the TCP/IP Properties dialog box
The gateway or router status
The remote computer is running the File And Printer Sharing For Microsoft Net. works Service (this service can be added in the TCP/IP Properties dialog box)

Using Tracert

When a route breaks down on the way from the destination computer to its target computer, communication fails. The Tracert command-line utility can help you figure Out exactly where along the route the breakdown happened. Sometimes the connection breaks down at the gateway on the local network and sometimes at a router on an external network.

To use Tracert, at the command prompt type tracert followed by the IP address of the remote computer. The resulting report shows where the packets were lost. You can use this information to uncover the source of the problem.

Using Pathping

The Ping command is used to test communication between one computer and another, Tracert: is used to follow a particular route from one computer to another. The Pathping command is a combination of both Ping and Tracert, displaying information about packet loss at every router between the host computer and the remote one. The Pathping command provides information about data loss between the source and the destination, allowing you to determine which particular router or subnet might be having network problems. To use the Pathping command, at the command prompt, type pathping followed by the target name or IP address.

The Windows Help And Support Center offers a list of all of the commands that you can perform by using the command line. Search for Command-Line Reference A-Z. Each command reference includes a description of the command and how to use It.

The TCP/IP Protocol Suite

The TCP/IP suite of protocols provides a set of standards for how operating systems and applications communicate and how networks are interconnected. The TCP/IP suite of protocols maps to a four~layer conceptual model known as the Department of Defense (DOD) model. The four layers are as follows:

Network access layer The network access layer is responsible for placing data on the network medium and receiving data off the network medium. This layer contains physical devices such as network cables and network adapters.

Internet layer The Internet layer is responsible for addressing, packaging, and routing the data that is handed down to it from the transport layer. There are four core protocols in this layer: IP, Address Resolution Protocol (ARP), Internet Control Message Protocol (ICMP), and Internet Group Management Protocol (IGMP).

Transport layer The transpon layer protocols provide communication sessions between computers. The desired method of data delivery determines the transport protocol. The two transport layer protocols are TCP and User Datagram Protocol (UDP).

Application layer At the top of the model is the application layer, in which applications gain access to the network. There are many standard TCP/IP tools and services in the application layer, such as File Transfer Protocol (FTP), Telnet, Simple Network Management Protocol (SNMP), DNS, and so on.

The purpose of this layering is to provide a level of abstraction between an application or protocol in one layer and the functioning of the entire network. For example, an application in the application layer needs to know only where to pass information into the transport layer (and how to format that information); it does not need to take into account any specific network configuration beyond that point. Packets of data are passed down the layers on the sending host and back up the layers on the receiving host.

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Mortal Kombat Legends: Scorpion's Revenge, trailer

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 21:22:00 +0000

the game that went viral after the coronavirus in wuhan

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 21:19:00 +0000

According to App Annie data, 'Plague Inc.' it was the most downloaded app in China on January 21 and in the United States on January 23, just the days we began to know about the virulence and lethality of what we called "mysterious Wuhan virus". This coincides with what was detected by Sensor Tower, seeing that on January 22 there was a very high rise compared to the previous days until 21.
'Plague Inc.' since the outbreak began.

It is a real-time strategy game in which the player's goal is to create a plague with a pathogenic organism to end humanity. So far, something killer fantasy, the "problem" is that it was designed to be realistic and informative about viruses and infectious diseases, and many users have taken it to the letter, too.

s

Programming is fun

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 21:08:00 +0000

Coding is fun !, or "programming is fun" is a simple but great online video game where you can learn the most basic principles of code by solving logic puzzles. Although it is mainly aimed at children aged 6 to 12, this does not mean that an adult cannot enjoy it and take advantage of it.

free download cisco ios images for gns3 dynamips dynagen

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 19:51:00 +0000

Free Download Cisco IOS Images for GNS3

In the case you may need Cisco IOS images for the GNS3 network simulator program.

Here I will leave a link where you can download and you can use at no cost the Cisco IOS images for GNS3 . Let me tell you that these Cisco IOS images will be compatible and workable for GNS3.

While you prepare for Cisco exams, with this link where you can download free image you will have no problems for the exam

As a result, you will not have problems with GNS3 while preparing for the Cisco exams.

free Cisco IOS images for gns3 from the next link

Cisco IOS for GN

most used topology

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 19:36:00 +0000

Bus: This topology allows all stations to receive the information that is transmitted, one station transmits and all other stations listen. It consists of a cable with a terminator at each end of which all the elements of a network are hung. All the nodes of the network are connected to this cable: which is called "Backbone Cable". Both Ethernet and Local Talk can use this topology.

The bus is passive, there is no regeneration of the signals in each node. The nodes in a "bus" network transmit the information and hope that it will not collide with other information transmitted by another of the nodes. If this occurs, each node waits a small amount of random time, then tries to relay the information.

Ring: The stations are connected to each other forming a circle by means of a common cable. The last node of the chain is connected to the first one by closing the ring. The signals circulate in only one direction around the circle, regenerating at each node. With this methodology, each node examines the information that is sent through the ring. If the information is not directed to the node that examines it, pass it to the next one in the ring. The disadvantage of the ring is that if a connection is broken, the entire network goes down

Star: The data in these networks flows from the sender to the concentrator, it performs all the functions of the network, also acts as an amplifier of the data.

The network joins at a single point, usually with a centralized control panel, such as a wiring hub. The information blocks are directed through the central control panel to their destinations. This scheme has an advantage by having a control panel that monitors traffic and prevents collisions and an interrupted connection does not affect the rest of the network

Hybrids: The linear bus, the star and the ring combine sometimes to form combinations of hybrid networks
Star Ring: This topology is used in order to facilitate network administration. Physically, the network is a centralized star in a hub, while at the logical level, the network is a ring.

"Bus" in Star: The end is equal to the previous topology. In this case the network is a "bus" that is physically wired as a star through hubs.

Hierarchical Star: This wiring structure is used in most current local networks, through cascading hubs to form a hierarchical network

Tree: This structure is used in cable television applications, on which future network structures that reach homes could be based. It has also been used in analog local broadband network applications.

Plot: This network structure is typical of WANs, but can also be used in some local network (LAN) applications. Workstations are connected to each other.

The three most used topologies are:

Central Link Network: It is generally found in office or field environments, in which the networks of the floors of a building are interconnected over central cables. Bridges and routers manage traffic between connected network segments.

Mesh Network: This involves or is done through WAN networks, a mesh network contains multiple paths, if a path fails or traffic is congested, a packet can use a different path to the destination. Routers are used to interconnect separate networks.

Hierarchical Star Network: This wiring structure is used in most of the current local networks, through cascaded hubs to form a hierarchical network

Network Topology

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 19:17:00 +0000

The network topology or logical network form is defined as the communication chain that the nodes that make up a network use to communicate. It is the geometric distribution of connected computers

Bus network

Network whose topology is characterized by having a single communications channel (called bus, trunk or backbone) to which the different devices are connected. In this way all devices share the same channel to communicate with each other.
The bus topology has all its nodes connected directly to a link and has no other connection to each other. Physically each host is connected to a common cable, so they can communicate directly. The cable break causes the hosts to be disconnected.

The ends of the cable are terminated with a coupling resistor called terminator, which in addition to indicating that there are no more computers at the end, allow the bus to be closed by means of an impedance coupling.

It is the third of the main topologies. The stations are connected by a single cable segment. Unlike a ring network, the bus is passive, there is no signal generation at each node.

Advantage

Ease of deployment and growth.
Economic.
Simplicity in architecture.

Disadvantages

Limited channel lengths.
A problem in the channel usually degrades the entire network.
Performance decreases as the network grows.
The channel needs to be properly closed (closed roads).
High transmission losses due to collisions between messages

STAR NETWORK

A star network is a network in which the stations are directly connected to a central point and all the communications that must necessarily be made through it.
Given its transmission, an active star network has an active central node that normally has the means to prevent echo related problems.

It is used mostly for local networks. Most local area networks that have a router, a switch, or a hub follow this topology. The central node in these would be the router, the switch or the hub, through which all packets pass.

Advantage

It has two means to prevent problems.
It allows all nodes to communicate with each other conveniently.

Disadvantages

If the central node fails, the entire network is disconnected.
It is expensive, since it requires more cable than the Bus and Ring topology.
The cable travels separately from the hub to each computer

Ring network

Network topology in which each station is connected to the next and the last is connected to the first. Each station has a receiver and a transmitter that acts as a repeater, passing the signal to the next station.

In this type of network the communication is given by the passage of a token or witness, which can be conceptualized as a mailman who passes collecting and delivering information packages, thus avoiding possible loss of information due to collisions.

It is worth mentioning that if any node in the network stops working, communication throughout the ring is lost.

In a double ring, two rings allow data to be sent in both directions. This configuration creates redundancy (fault tolerance), which means that if one of the rings fails, the data can be transmitted by the other.

Advantage

· Simplicity of architecture. Ease of implesion and growth.

Disadvantages [edit]

· Limited channel lengths.
· The channel will usually degrade as the network grows.

Mesh network

The mesh topology is a network topology in which each node is connected to all nodes. In this way it is possible to take messages from one node to another by different paths. If the mesh network is completely connected, there can be absolutely no interruption in communications. Each server has its own connections with all other servers.

The establishment of a mesh network is a way to route data, voice and instructions between nodes. Mesh networks differ from other networks in that the elements of the network (node) are all connected to all, by separate cables. This configuration offers redundant paths throughout the network so that, if one cable fails, another will take care of the traffic.

This topology, unlike others (such as tree topology and star topology), does not require a central server or node, which reduces maintenance (an error in a node, whether important or not, does not imply the fall of the entire network).

Mesh networks are auto routable. The network can work, even when a node disappears or the connection fails, since the rest of the nodes avoid passing through that point. Consequently, the mesh network is transformed into a very reliable network.

It is an option applicable to wireless networks (Wireless), wired networks (Wired) and node software interaction.

A network with mesh topology offers superior redundancy and reliability. Although the ease of troubleshooting and increasing reliability are very interesting advantages, these networks are expensive to install, since they use a lot of wiring. Therefore, they become more important in the use of wireless networks (due to the lack of wiring) despite the inconveniences of Wireless.

In many cases, the mesh topology is used together with other topologies to form a hybrid topology. It is connected to a server that sends other computers
A mesh network effectively extends a network, sharing access to a larger infrastructure.

Tree network

Network topology in which the nodes are placed in the form of a tree. From a topological view, the tree connection is similar to a series of interconnected star networks except that it does not have a central node. Instead, it has a trunk link node, usually occupied by a hub or switch, from which the other nodes branch. It is a variation of the bus network, the failure of a node does not imply interruption in communications. The same communications channel is shared.

The tree topology can be seen as a combination of several star topologies. Both the tree and the star are similar to the bus when the interconnection node works in broadcast mode, since the information is propagated to all stations, only in this topology the branches extend from a root point ( star), as many branches as possible, depending on the characteristics of the tree.

types of network cables

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 18:52:00 +0000

MAIN TYPES OF CABLES

The vast majority of networks are connected by some type of wiring, which acts as a means of transmission where the signals pass between the equipment. A large number of cable types are available to meet the needs and sizes of different networks, from the smallest to the largest.

There are a lot of types of cables. Some manufacturers publish a catalog with more than 2000 different types that can be grouped into 3 groups:

COAXIAL CABLE

A coaxial cable consists of a core of copper wire surrounded by an insulator, a braided metal shield and an outer sheath. The term shielding refers to the braided or metal mesh that surrounds some types of cable. The shield protects the transmitted data by absorbing spurious electronic signals, called noise, so that they do not pass through the cable and do not distort the data. The cable containing an insulating sheet and a braided metal shielding layer is called a double shielded cable. For environments that are subject to large interference, a quadruple shield is available. This shield consists of two insulating sheets and 2 layers of braided metal shielding.

TYPES OF COAXIAL CABLES

There are two types of coaxial cable:

FINE CABLE (THINNET)

THICKNET CABLE

THINNET CABLE: is a flexible coaxial cable about 0.64 cm thick. It can be used for most types of networks, it is a flexible cable and easy to handle. It can support a signal of an approximate distance of 185 m, before the signal begins to suffer attenuation. It is included in a group called THE RG-58 FAMILY and has an impedance of 50 ohm.

THICKNET CABLE: It is a 1.27 cm rigid coaxial, sometimes referred to as standard ETHERNET because it was the first type of cable with the Ethernet network. The greater the thickness of the copper core, the farther it can carry the signals. It can carry a signal of 500 meters. It is used as a central link or backbone to connect small networks based on thinnet.
A TRANSCEIVER designed for Ethernet, thicknet includes a connector known as VAMPIRO or FORADOR to establish the connection to the thicknet core.
THERE ARE TWO TYPES OF BRAIDED TORQUE CABLES

- UNPLASHED BRAIDED TORQUE CABLE (UTP)

SCREENED TWISTED TORQUE CABLE (STP)

A series of twisted pair wires are often grouped together and enclosed in a protective sheath to form a cable. Braiding eliminates electrical noise from adjacent pairs and other sources such as motors, networks and transformers.

UNPLASHED BRAIDED TORQUE CABLE (UTP)With the 10baset specification, it is the best known type of twisted pair cable and has been the most used LAN wiring. The maximum cable length segment is 100 meters. It consists of 2 insulated copper wires the specifications dictate the number of interlocks allowed per cable foot; The number of interlocking depends on the purpose with which the cable is installed.

SCREENED TWISTED TORQUE CABLE (STP)Use a wrap with braided copper, more protective of higher quality than used in the utp cable. Stp also uses a foil surrounding each of the pairs of wires, offers excellent shielding in the stp to protect the transmitted data from external intermodulations, allowing it to withstand higher transmission rates than the utp at greater distances.

OPTICAL FIBER CABLE

This signals that are transported are digital data signals in the form of light modulated pulses. It is suitable for transmitting data at very high speeds and with large capacities. It consists of an externally thin glass cylinder, called a nucleus, covered by a concentric glass layer called a coating sometimes made of plastic.

Wireless transmission: they are radio waves are easy to generate, they can travel long distances and penetrate the building without problems, they are omnidirectional travel in all directions from the source, so the transmitter and receiver do not have to line up.
Microwave transmission: above 100 mhz the waves travel in a straight line can be focused on a narrow sickle. Concentrating all the energy in a small sickle with a satellite dish produces a much higher signal in relation to noise, but the transmitting and receiving antennas must align with each other.

Infrared waves: do not cross solids is an advantage so that an infrared system does not interfere with a similar system on an adjacent side. This system does not need a government license to operate in contrast to radio systems.
Transmission by light waves: it offers a very high bandwidth and a very low cost. Easy to install and does not require a license. The disadvantage is that laser beams do not penetrate rain and fog.

Wireless networks: they facilitate the operation where the computer cannot remain in one place, the current wireless networks offer speeds of 2mbps.

Types of Network Topology

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 18:32:00 +0000

TOPOLOGY: or logical form of a network is defined as the way to lay the cable to individual workstations; by walls, floors and ceilings of the building. There are a number of factors to consider to determine which topology is most appropriate for a given situation. The topology in a network is the configuration adopted by the workstations to connect to each other.

BUS TOPOLOGY

Network whose topology is characterized by having a single communications channel called a trunk bus or backbone connects to different devices or other nodes.

ADVANTAGE:

Ease of implementation
Growth and simplicity of architecture

DISADVANTAGES:

Limited channel lengths
A problem in the channel usually degrades the network

DOUBLE RING TOPOLOGY

It consists of two concentric rings where each network is connected even or more rings although the two rings are not connected to each other.

ADVANTAGE:

Architecture Simplicity
Ease of deployment and growth

DISADVANTAGES:

The channel usually degrades the network

TREE TOPOLOGY

It is a cable of ramifications and hierarchical information flow.

ADVANTAGE:

The wiring is point to point for individual segments
Support from a multitude of software and hardware vendors

DISADVANTAGES:

The size of each segment is determined by the type of cable if the segment falls apart.

RING TOPOLOGY

It consists of a single ring

ADVANTAGE:

Architecture Simplicity
Ease of implementation

DISADVANTAGES:

The channel usually degrades the network

STAR TOPOLOGY

It is the physical way in which all stations were connected to a single central node.

ADVANTAGE:

It allows the communication of the other nodes, presents means to prevent problems
Economic maintenance

DISADVANTAGES:

If the hub fails the network has no communication if the central node fails the entire network is disconnected

NETWORK TOPOLOGY

It is similar to the star topology, except that it has no central nodes.

ADVANTAGE:

Point to point wiring

DISADVANTAGES:

If the main segment fails, the entire network collapses

MESH TOPOLOGY

In which each node is connected to all nodes in this way it is possible to take messages from one node to another by different paths.

ADVANTAGE:

Offers superior redundancy and reliability
They are routable

DISADVANTAGES:

It is of low efficiency of connections and links due to the existence of redundant links

ELEMENTS OF A NETWORK

noreply@blogger.com (fenix) — Wed, 29 Jan 2020 18:15:00 +0000

SERVER: it is the main processing element, it contains the network operating system and is responsible for managing all the processes within it, it also controls access to common resources such as printers and storage units.

WORKSTATIONS: sometimes called nodes, they can be personal computers or any terminal connected to the network. You work with your own programs or take advantage of existing applications on the server.

NETWORK OPERATING SYSTEM: it is the program that allows the control of the network and resides in the server.

COMMUNICATION PROTOCOLS: they are a set of rules that regulate the transmission and reception of data within a network.

NETWORK INTERFACE CARD: provides the connectivity of the terminal or user of the physical network, since it handles the communication protocols of each specific topology.

WIRING: is the cable that is going to be used in the network that is physical is called utp.

HUB OR CONCENTRATOR: in communications, distribution center, hub. A Hub is a network device that allows other computers or devices to connect to each other by retransmitting data packets from any of them to everyone. They have stopped being used because of the large number of collisions and network traffic they produce.

SWITCH: it is a digital device of interconnection logic of computer networks that operates in layer 2 (data link level) of the osi model: its function is to interconnect 2 or more network segments, similar to bridges (bridges), passing data from one segment to another according to the Mac address of different frames in the network.

The switches are used when you want to connect multiple networks, merging them into one. Like bridges, since they function as a filter in the network, they improve the performance and security of the lans.

REPEATER: it is an electronic device that receives a weak or low level signal and retransmits it to a higher power or level, so that longer distances can be covered without degradation or with tolerable degradation. The term repeater was created with telegraphy and referred to an electromechanical device used to regenerate telegraphic signals. The use of the term has continued in telephony and data transmission.

BRIDGE : it is a computer network interconnection device that operates in layer2 (data link level) of the osi model. It interconnects 2 network segments by passing data from one network to another, based on the physical destination address of each package. A bridge connects 2 network segments as a single network using the same network establishment protocol. It works through a table of Mac addresses detected in each segment to which it is connected. When it detects that a node of one of the segments is trying to transmit data to a node of the other, the bridge copies the frame for the other subnet. By using this machine learning mechanism, bridges do not need manual configuration.

The main difference between a bridge and a hub is that the second passes any frame with any destination for all other connected nodes, instead the first only passes frames belonging to each segment. This feature improves network performance by reducing useless traffic.

To make the bridging or interconnection of more than 2 networks, the switches are used.

ROUTER: It is a general purpose device designed to segment the network, with the idea of limiting brodcast traffic and providing security, control and redundancy between individual brodcast domains, it can also provide firewall service and economic access to a WAN. It operates in layer 3 of the osi model and has more software facilities than a switch. When operating on a layer greater than that of the switch, the router distinguishes between different network protocols, such as ip, ipx, apple talk or decnet. This allows you to make a smarter decision than the switch, when forwarding packets.

GATEWAY: A device that is frequently a computer, which allows networks to be interconnected with protocols and different architectures at all levels of communication. Its purpose is to translate the protocol information used in a network to the protocol used in the destination network.

The IP address of a Gateway (or gateway) often resembles 191.167.1.1 or 191.166.0.1 and uses some predefined ranges, 127 xxx, 10 xxx, 172 xxx, 192 xxx, which encompass or reserve networks local, also it should be noted that necessarily a team that fulfills the role of gateway in a network, must have 2 network cards.

MODEM: It is a device used to modulate and demodulate a signal called carrier by another input signal called modulator. The modulating signal constitutes the information that is prepared for a transmission (a modem prepares the information to be transmitted, but does not perform the transmission). The modulator modifies some characteristic of the potador so that a signal is obtained, which includes the information of the modulator. Thus the demodulator can recover the modulating signal can recover the original modulating signal, removing the carrier. The characteristics that can be modified from the carrier signal are:

• Amplitude, resulting in an amplitude modulation (am / ask).

• Frequency, resulting in a frequency modulation (fm / fsk).

• Phase, resulting in a phase modulation (pm / psk).

Space Weather Woman

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 23:38:00 +0000

In his YouTube channel, Space Weather Woman, the space predictions have to do with storms, but with solar or Martian; also with the storms but those in the solar corona or on the moon of Jupiter Europe and with phenomena such as eclipses and transits, such as Mercury. It reminded me a little of the Martian meteorology page that NASA has
s

The father passed out in the operating room while the woman gave birth, and the picture of the moment goes viral

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 23:31:00 +0000

He wanted to support his wife in childbirth, and in the end it was he who needed help. s

View this post on Instagram

He was here to encourage his wife at her First Childbirth 😂

A post shared by Worth Feed (@worthfeed) on Jan 14, 2020 at 4:18am PST

Kupata, the dog that helps daycare children pass the street and scolds drivers if they don't respect the zebra crossing

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 23:26:00 +0000

image credit Facebook Batumi, Adjara
These Facebook images, shared by different users of this social network, have been reproduced more than a million times since January 20.

You can see how Kupata barks at drivers who don't stop at the zebra crossing, demanding that they stop and allow children to cross across the street from their teacher's hand. s

Fast & Furious 9 teaser trailer

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 22:57:00 +0000

Streaming how China builds a hospital for the coronavirus in ten days

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 22:47:00 +0000

Now, more than eight million people are congregating on the Yangshipin website to see how China builds its hospital for Wuhan's coronavirus in less than ten days. s

Facebook publishes the tool that shows how they track everything you do on the web even when you don't use Facebook or Instagram

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 22:41:00 +0000

Having promised more transparency in the way they collect and use user data, Facebook has finally launched a tool that they say "provides us with more control over our data." Its name is' Off-Facebook Activity 'or' 'Activity outside of Facebook', and it is basically what its name indicates: a sample of everything Facebook collects about our activity on the web outside its services.
On the Activity page outside of Facebook you will find all the information that companies and organizations that share data with Facebook keep about you. This includes all kinds of interactions we make with applications, pages or web services that are not part of Facebook, but that also send data of what you do to the Mark Zuckerberg company.
You can also download all your information or access it in a category view
Off-Facebook activity includes information that businesses and organizations share with us about your interactions with them, such as visiting their apps or websites. Learn More

What Is Automatic Private IP Addressing?

noreply@blogger.com (fenix) — Tue, 28 Jan 2020 00:09:00 +0000

What Is Automatic Private IP Addressing?

The Windows 10 implementation of TCP/IP supports automatic assignment of IP addresses for simple LAN-based network configurations. This addressing mechanism is an extension of dynamic IP address assignment for LAN adapters, enabling configuration of IP addresses Without using static IP address assignment or using a DHCP server. Automatic Private IP Addressing (APIPA) is enabled by default in Windows 10 so that home users and small business users can create a functioning, single-subnet, TCP/IP-based network without having to configure the TCP/IP protocol manually or set up a DHCP server.

The IANA has reserved 169.254.0.0 through 169.254.255.255 for APlPA. As a result, APIPA provides an address that is guaranteed not to conflict with routable addresses.

APIPA assigns an IP address and subnet mask only, and configures no additional parameters. This service is very useful in smaller, single-network environments in Which there is no need for connectivity to other networks. APIPA provides a very pie way to configure TCP/IP; the network administrator does not need any know of the necessary configuration parameters. However, if connectivity to other networks is required, or if the client requires name-resolution services, APIPA is not sufficient. APIPA does not provide a default gateway or name server address to the client.

The process for the APIPA feature, is explained in the folk»Mn steps:

1. Windows 10 TCP/IP attempts to find a DHCP server on the anached network to obtain a dynamically assigned IP address.

2. In the absence of a DHCP server during startup (for example, if the server is down for maintenance or repairs), the client cannot obtain an IP address.

3. APIPA generates an IP address in the form of 169.254.x.y (where x.y is the client‘s randomly generated unique identifier) and a subnet mask of 255.255.0.0.

After the computer generates the address, it broadcasts to this address, and then assigns the address to itself if no other computer responds. The computer continues to use this address until it detects and receives configuration information from a DHCP sewer. This allows two computers to be plugged into a LAN hub to restart without any IP address configuration and to use TCP/IP for local network access.

If the computer is a DHCP client that has previously obtained a lease from a DHCP server and the lease has not expired at boot time, the sequence of events is slightly different. The client tries to renew its lease With the DHCP server. If the client cannot locate a DHCP server during the renewal attempt, it attempts to ping the default gateway listed in the lease.

1f pinging the default gateway succeeds, the DHCP client assumes that it is still on the same network in which it obtained its current lease, so it continues to use the lease. By default, the client attempts to renew its lease when 50 percent of its assigned lease time has expired. If pinging the default gateway fails, the client assumes that it has been moved to a network that has no DHCP services currently available and it autoconfigures itself, as previously described. After being automatically configured, the client continues to try to locate a DHCP server every five minutes.

APIPA can assign a TCP/IP address to DHCP clients automatically. However, APIPA does not generate all the information that typically is provided by DHCP, such as the address of a default gateway. Consequently, computers enabled with APIPA can communicate only with computers on the same subnet that also have addresses of the form 169.254.x.y.

If you are troubleshooting a network problem and discover that a client computer has an IP address on the 169.254.0.0 network, the computer has assigned itself that address using APIPA because the computer could not locate a DHCP server.

By default, the APIPA feature is enabled. However, you can disable it by specifying an alternate configuration to use if a DHCP server cannot be located in the alternate configurations on internet protocol properties

Was the Star Wars Galaxy Better Off After Return of the Jedi or The Rise of Skywalker?

noreply@blogger.com (fenix) — Mon, 27 Jan 2020 23:33:00 +0000

photo credit lucasfilm
As the final chapter in a trilogy of trilogies, Star Wars: The Rise of Skywalker puts a period on what fans have long known as the main story of Star Wars. It also offers a chance to look at the galaxy moving ahead and see how its conclusion compares to the previous ones. read the full story here

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Space Weather Woman

The father passed out in the operating room while the woman gave birth, and the picture of the moment goes viral

Kupata, the dog that helps daycare children pass the street and scolds drivers if they don't respect the zebra crossing

Fast & Furious 9 teaser trailer

Streaming how China builds a hospital for the coronavirus in ten days

Facebook publishes the tool that shows how they track everything you do on the web even when you don't use Facebook or Instagram

What Is Automatic Private IP Addressing?

What Is Automatic Private IP Addressing?

Was the Star Wars Galaxy Better Off After Return of the Jedi or The Rise of Skywalker?

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