Category: Computers

What is SSL Secure Socket Layer

SSL is short for Secure Socket Layer which is a transport layer protocol that is used in a secure internet connection. If you want a communication connection via the internet with a secure technique, then use an SSL connection.

SSL offers three levels of security, namely:

  • Authentication: Ensures that the message received is from someone who is explicit
  • Confidentiality: Protects messages from a reading effort by recipients who are not eligible throughout their journey.
  • Integrity: Ensuring that the original message, does not feel a change in its journey.

The first two you can get from your ISP, contact your ISP to convince him.

SSL operates between the Application and Transport layers in the OSI model. SSL does not work transparently automatically, because only if the application protocols are explicitly implemented.

SSL uses public-key encryption for the purpose of authentication and symmetric key encryption to encrypt the information sent. For public SSL encryption keys, use the Rivest-Shamir-Adleman (RSA) encryption algorithm, so it depends on the implementation of the supported infrastructure public key (PKI). Message integrity is ensured by an integrity checking mechanism technique called a message authentication code (MAC).

Authentication process

An SSL session starts when an SSL-enabled client requests a connection with a server with SSL-enabled over TCP port 443, the SSL port. This will initiate an SSL connection between the client and server. All sites that use SSL have a URL with the HTTPS prefix. The server then sends the digital certificate and public key to the client.

The client server then negotiates which level of encryption can be received which is often 40-bit, 56-bit, or 128-bit and above. The client then generates a secret session key which is then encrypted using the public key from the server to send it to the server. The server then decodes the secret session key using the private key. From this point onwards, the secret key cryptography is imposed and then the session key is used to encrypt all data exchanges between the client and the server, leaving a secure private communication.

SSL is certainly not free from problems. All web transactions with SSL will increase processing overhead on the server. Sometimes it is double the process overhead compared to using a secure SSL connection. With the same machine hardware, the processing load level using SSL will be the heaviest compared to without SSL.

Besides that, SSL is difficult to implement in e-commuters that use web server farms and server load balancers. This view of SSL is designed so that the client uses the same IP address around the session.

To overcome this problem, often used exclusive hardware called SSL Accelerators to collect processing fees and cache sessions for different servers to increase performance.

Computers

Introduction of Types of Computer Networks

A network is a collection of desktop or laptop computers and other network devices such as printers that are connected together with the main destination is to communicate with each other and exchange data with each other. The core of computer networks is sharing and allowing your computer to connect to the internet, communicate with each other, and share resources like files and printers.

Network benefits

With the network, you will get a lot of flexibility in your work and provide time together with computers and electronic equipment. With a computer network you can:

  1. You can share one broadband internet connection to the point that everyone on your network can simultaneously surf – surf the internet – so it doesn’t take turns.
  2. You can access your email account while surfing and digging different data
  3. Can share all kinds of files like documents, belonging to music, digital images, and other documents.
  4. You can store your music, image, and file libraries into one place, a storage media, for example NAS (network access storage). That way you can access your music file from anywhere in your home via the network.
  5. Can save your computer against attacks from the internet such as viruses, worms, hackers etc. centrally. See also Pacth management
  6. You can watch one-on-one game games, or online multiplayer games with your family and even with your colleagues all over the world
  7. You can save money by simply buying one printer, storage media, or other equipment to be used simultaneously through the network. See also network sharing printers.

There are so many benefits with the network, you can share storage and access files on other computers through the network that is in your home or commonly called a LAN (local location network) network. It doesn’t matter where you save the file, you can always access it, of course with certain restrictions. And if you use share storage, you don’t need to have to turn on your computer so that other computers can access it. You can also save your files on different computers / storage on the Internet or commonly called WAN (wide location network).

Network Type

There are not a few types of networks according to the size and proximity. And almost everything can be categorized into two basic collections namely local location network (LAN) and wide location network (WAN).

Local Network

A LAN is a network of a set of computers, printers, or other network equipment that is connected to one another in different ways as in a home, office, or school and campus. This allows users who are connected to the network to share files, printers, or storage together. Whether this network consists of only two computers or in the largest scale, the main destination is so that each user can share information quickly and easily. So often a LAN is limited to a distance in one building or location that can communicate with each other quickly.

WAN network

While a WAN is a group of computer networks on a large scale across geographic boundaries, such as between cities or between countries. A simple example of a WAN network is the Internet where all computers in all worlds can be interrelated and communicate (of course with certain limitations). A router is needed to communicate with each other between your personal LAN network and the WAN network using a common network protocol called TCP / IP.

The picture above indicates a concept diagram of a network where a LAN network is connected to a WAN (internet) network using a router.

There are two main types of networks:

  1. Wired or wired network – Communication over a data cable – commonly using an Ethernet base
  2. wireless network – data communication passes through radio waves

It is most common for networks home or office to use a combination of both: cable and wireless.

Why choose a cable network?

Wired (cable) networks have been around for decades. Wired network technology that is now very popular is Ethernet networks. Data cables, commonly referred to as Ethernet network cables (CAT5), are used to connect computers and other network equipment that make up the network. A wired network is very good if you need a large amount of data transfer with the highest speed and reliable, just call it for gaming and entertainment media like HD (high definition) video.

The advantages of a wired network are the following:

  1. Actual cheap costs
  2. Offer the highest performance
  3. High speed – the standard speed of Ethernet cable is 100 Mbps
  4. Higher speed – Gigabit Ethernet cable up to 1000 Mbps

Why use wireless networks?

Wireless networks do not use cables to connect to each other. however they will use radio waves like your cellular telephone. The main advantage of wireless networking is that it is mobile (mobile) and free from a cable or fixed connection limitation. The advantages of wireless networks are the following:

  1. The nature is mobile and free – you can play from anywhere in the wireless network signal coverage
  2. Not limited to cable connections or fixed connections.
  3. Fast installation and not difficult, do not need to drill the wall to penetrate it for network cable needs
  4. No need to purchase a network data cable to the point that it saves times and is not complicated
  5. Easy to develop

With wireless networks you can use your computer anywhere in your home or office, even in the park or in your gazebo. You can check email and browsing or online or even you can print wirelessly from other rooms. we don’t need to drill holes to install Ethernet network cables to break down walls. You can connect to a wireless network. Outside the house you can connect with public hotspot networks such as cafes, airports, hotels, campuses etc. This is very suitable for those who often travel.

3G / 4G network

Even now there is a widespread cellular network (3G / 4G network) that can be accessed through certain cellular phones, and you can also share one 3G connection account with a number of people using a 3G modem and 3G router, call it DIR-450/451 from D-Link or Cradlepoint CTR-500.

The heart of a home network is a router. Even though there are two types of routers that encapsulate wired and wireless, a wireless router can do everything like what can be done on a wired router, and give up more flexibility and even the same price. Call it the E-Series wireless router from Linksys, or call it Netgear WNDR37AV for gaming and video.

Almost all wireless routers are equipped with at least 4 Ethernet ports, both Fast Ethernet or Gigabit Ethernet. With a laptop you can roaming all over your house without wires, or the PC is located next to the router can use wired connections for high reliable speeds. For convenience and wireless networking facilities is the answer.

Wireless Performance

The maximum performance of a wireless is obtained from the IEEE 802.11 standard specification. actual performance can vary, including lower wireless network capacity, data rate throughput, coverage and range. Performance can depend on not a few factors, situations and variables, classified as distance from the access point (base station), network traffic volume, construction and building materials, operating system used, combined or used wireless products, interference and other situations.

Standard Wifi

Here are some types of 802.11 wireless standards

Wireless-A (802.11a)

The 802.11a wireless standard operates at a frequency of 5 GHz which is not quite booming compared to a 2.4 GHz freq where telephone and microwave can cause interference. Even though the speed is up to 54 Mbps, the range is only 25 meters. Wireless A is not compatible with wireless B / G and N because it operates on a different frequency.

Wireless-G (802.11g)

Almost the same as wireless B, but the speed can be up to 5 times up to 54 Mbps. You can mix wireless B and G, but you will lose fast performance from wireless G.

Wireless-N (802.11n)

Wireless 802.11n is the latest and very fast wireless generation of up to 300 Mbps and even up to 450 Mbps (for example in TEW-691GR from Trendnet). It is appointed with Multiple Input, Multiple Output (MIMO. Wireless N is very suitable for applications that are hungry for bandwidth like streaming HD video, voice and music.

Wireless AC (802.11ac)

Wireless AC is the fifth generation of WiFi technology that can penetrate speeds in theory to 1300Mbps at 5GHz bands. 802.11ac is the latest wifi technology that has begun to be adopted for wireless routers, wireless adapters or wireless bridges with aggregate speeds of up to 1750Mbps. Call it Netgear with R6300 wireless ac router, Linksys with EA6500 ac router and not a few more.

Dual band

Dual-band routers work on both 2.4 GHz and 5 GHz frequencies. Some wireless routers working between bands only or a number also work together in both bands. With dual-band, it will minimize interference and leave more bandwidth for software such as video streaming.

Building networks

Here are the requirements that you need to build an internet network at home or in an office.

Router

The router is the heart of your home network and it is a device that forwards all traffic to and from the internet and the opposite in your network. With the router you can also share an internet connection from your ISP to a number of computers on the network. Routers are also useful as a security layer from the threat of internet security.

High speed internet service connection (Cable or ADSL)
You can buy a high speed internet service from your ISP (internet service provider) for example from Telkom Speedy service. we can also create an Internet network using Cellular services. Of course using a router that is contradictory, say MEBR3500 from Netgear or MBR1200 from Cradlepoint. Common high-speed internet services are referred to as broadband internet to separate with dial-up.

Modem

Modems are useful for connecting broadband internet services to your computer so you can surf the internet and access your email. Depending on your broadband Internet service, either Cable or ADSL, you must adjust the modem. often the ISP spends a modem when you sign an internet service agreement at your home. A gateway router is an integrated device that includes the modem and router if DGND3300 from Netgear.

Network Adapter

Network adapters allow your computer to be connected to a network. if your computer already has an adapter in it you don’t need to buy it again. There are not a few types of adapters depending on the computer you are using.

For desktop computers:

  1. You can use a PCI adapter that can be inserted in your computer’s PCI slot by opening the casing of course.
  2. Or you can use a USB adapter with the technique of inserting it into a USB port on your computer without having to open the computer case to the point that it is more practical.

For Laptops you can use:

  1. PC Card (PCMCIA) which is the adapter for your credit card, tuck in your laptop slot.
  2. ExpressCard, an exclusive laptop that has an ExpressCard slot
  3. USB adapter, the most practical and simple.

To find maximum performance, you must compare the adapters and routers that you use. For example, the wireless router that you use is from the dual-band 802.11n standard (for example Linksys WRT610N or DIR-855 D-Link), then you also have to use an adapter with the same wireless standard that is a dual-band wireless N call it WUSB600N from Linksys or TEW-644 USB dual-band adapter.

Computers