Who can read the file. If the file is read a list, the list of directory contents.
Who can write / edit the file. If the file is a directory that provides such a permit if you make changes to the Content directory, such as creating or deleting files.
Who can run the file. If the file is a directory that provides such a permit if you enter the directory and access to these pages, such as looking for the implementation of an inventory or run a program in it.

The permissions are assigned to the file owner, group owner of the file, and all users. For example, you can specify that a document must be readable and writable by owner only, and only readable by everyone.

If you have a ls, controls everything, to question the contents of a directory, you are the permissions of files, such as those next to each file, see:

-Rwxrwxrwx

This means that read this file can be written and directed by no one. The first line indicates that this file is not a directory. For directories, it will be a letter ad instead of a dashboard.

The first series, Äúrwx, AU refers to the owner of the file. The second series, the owners of the group. The last sentence, all other users. Or a couple of examples AOS:

-Rwxr – r – - -
This file can be read, written and directed by its owners. It can not be read by other users. If a permit is not defined, you will see a panel in his place.

-Rw-rw-r -
This file can be read and written by his owner and the owner of the group. It can not be read by other users.

You can use these permissions with the chmod command. For example, type this command:

chmod ugo = rwx file

assigns read, write and execute for the file owner (u), group (g) and other (o). This example further:

chmod ug = rw filename = r o

assigned read and write permissions for the user and group permission to read for others.

Permits may also be expressed and defined with the octal numeric system. Each license is associated with a number:

Read = 4
Write = 2
Run = 1

You must come with a number for the owner of the file, a different number for the group and one for other users. If you want to read, write and execute permissions for the owner to assign the file, add the three values to obtain a seventh If you want to assign the same permissions for the group and others, come with September 3, these permissions as follows:

chmod 777 file

If permissions for a file with the command:

chmod 764 file

then Aore establishing these permissions: Read, Write and Execute for the owner of the file (4 2 1 = 7), read and write access to the group (4 2 = 6) and for others to read (4).

The following commands are equivalent:

chmod ug = rw filename = r o
chmod 664 file

The pattern of temporary files allows you to implement security policies. This is not a good idea to file permissions high (eg 777) for all files. It is important to examine and assign permissions on files so that users do their work, and we are sure that every file accessible only by the right people.

Forest: The forest is the outer limit of an Active Directory structure. This is a group of multiple domain trees that share a common pattern, but do not form a contiguous namespace. It arises when the first computer is installed on an Active Directory network. There are at least a forest in a network. The first domain in a forest is a root domain. It controls the schema and domain name for the entire forest. It can be removed individually from the forest. Administrators can then create multiple forests and trust relationships between certain areas in these forests, according to organizational requirements.

Trees: a hierarchical structure in different areas of the Active Directory forest is organized as a tree. It is a root domain and several child domains. The first domain is created in a tree, the root domain. Each domain added to the root domain is their child, and the root domain is the parent company. The parent-child continues until the end node is reached. All areas share a common pattern tree, which is defined in the woods. According to the organizational needs, multiple domain trees are included in a forest.

Domains: A domain is the basic organizational structure of a model for the integration of Windows Server 2003. It logically organized resources on a network and defines a security boundary in Active Directory. The list can have more than one area, and each goes his own domain security policy and trust relationships with other domains. Almost all organizations with a kind of Wide Area Network with network model to improve network security and enable administrators to efficiently manage the entire network.

Objects: Active Directory stores all network resources as objects in a hierarchical structure of containers and sub-containers, so they easily accessible and manageable. Each object class consists of several attributes. Each time a new object is created for a certain class, it automatically inherits all the attributes of their class member. Although Windows Server 2003 Active Directory objects have defined a standard set, administrators can modify according to their organizational needs.

Organizational Unit (OU): It is the least abstract component of Windows Server 2003 Active Directory. It acts as a container, in which the resources of an area can be placed. The logical structure is similar to the functional structure of an organization. It allows to create administrative boundaries within a domain by a transfer of administrative tasks to different administrators in the field. Administrators, several organizational units in the network. You can also OUs nesting, which means that other organizational units can be created within an OU.
In a large and complex network is the Active Directory a single point of management for administrators, by all network resources in one place. It allows administrators to delegate administrative tasks efficiently and to facilitate the rapid discovery of network resources. It is easily adaptable, which means that administrators can a large number of resources to add, without an additional administrative burden. It is performed by partitioning the directory database to distribute in other areas, and to build trusting relationships that the users the benefits of decentralization and at the same time, centralized administration.

The physical network infrastructure of Active Directory is far too easy in comparison to its logical structure. The physical components are domain controllers and sites.

Domain Controller is Windows Server 2003 with Active Directory services and running as a domain controller. A local domain controller decides on requests for information about the objects in this area. A domain can have multiple domain controllers. Each domain controller in a domain follows the multimaster model by a complete copy of the directory partition of the domain. In this model, each domain controller contains a master copy of the directory partition. Administrators can use a domain controller, the Active Directory database to change. Changes are made by administrators are automatically replicated to other domain controllers in the domain.

However, there are operations that are not on the multi-model. Active Directory manages the operations and carry it assigns a single domain controller. This domain controller as a master operations. The master carries out several operations roles, which have forest-wide and the whole area.

Forest-wide roles: There are two types of rolls through the forest:

Schema Master and Domain Naming Master. The scheme is for the maintenance of the plan and distribute to the entire forest. The Domain Naming Master is responsible for maintaining the integrity of the forest area by recording additions and deletions to the areas of forest. If new fields are added in a forest, the role of the domain naming master is interviewed. In the absence of this role can create new fields are added.

Domain-level roles: There are three types of domain-level roles: RID Master, PDC Emulator and Infrastructure Master.

RID Master: The RID Master is one of the operations master roles that exist in each domain in a forest. It checks the sequence number for the domain controllers in a domain. It offers a unique sequence of RIDs to each domain controller in a domain. When a DC creates a new object, the object is a unique identifier of the security that is associated with a combination of a domain SID and RID. The domain SID is an identifier constant, while the RID is assigned to each object by the domain controller. The domain controller is the RID Master RID. If the domain controller, all supplied by the RID RID master, it asks the RID Master to issue more going on to create other objects in the area. If a domain controller and its pool of RIDs, the RID master is unavailable exhausted, no new object in the domain can not be created.

PDC Emulator: The PDC emulator is one of the five operations master roles in Active Directory. It is used in a domain with non-Active Directory computers. It processes password changes for users and computers, reproduced these updates to Backup Domain Controller, and running the domain master browser. If a user does not authenticate a domain controller for domain authentication, and the domain controller, the user due to bad password, the request to the PDC emulator is forwarded. The PDC emulator then verifies the password, and if it finds the entry update request the password, it authenticates the request.

Director of Infrastructure: The Infrastructure Master role is one of the operations master roles in Active Directory. It operates at the domain level and exists in every area of the forest. It supports all object references, inter-domain updating references from objects in its domain to objects in other domains. It plays a very important role in a multi-domain environment. He compares his data with a global catalog, which always has updated information about the objects from all domains. If the infrastructure master finds data that is outdated, it requests the global catalog for the updated version. If the current data in the global catalog is available, the infrastructure master replicated extracted data and updates to all other domain controllers in the domain.

Domain controllers can also acts as a global catalog servers are assigned. A GC is a special database that stores a replica of the Active Directory directory to its host domain and the partial replica directory other domains in a forest. It is standard on the first domain controller in the forest. He served mainly on the following connection options and queries to Active Directory:

It enables network logon by providing universal information belonging to a group with a domain controller when a logon request is initiated.

It allows find the directory information in all areas in an Active Directory forest.

A global catalog is necessary to connect a network within a multi-domain environment. Provision of information on worldwide compliance group, it improved the response times for queries. In his absence, a user is allowed to connect to its local domain only if the user is outside the local domain.

Website: A website is a group of domain controllers that exist on different IP subnets and are connected via a fast and reliable network. A network can connect multiple sides of a WAN link. The pages are for replication traffic, which can occur at a site or between sites to check. Replication in a place called intersite replication, and that is between the sites as a cross-site replication. Like all domain controllers in a site, usually with a fast LAN connection, is the site replication are always uncompressed. Any changes in the field are quickly replicated domain controllers. Since the locations are connected via a WAN connection, the inter-site replication is still in compressed form. Therefore, it is slower than the inter-site replication.

The issue of Internet connectivity is addressed in several ways, including the use of Wi-Fi, WiMax, 3G and satellite and fiber optics, coaxial cable and the Plain Old Telephone. Competition, deregulation and the fact that the developing world is now the only new telecommunications market, all contribute to a wider availability, higher bandwidth, especially in those countries, the cost of lower connectivity.

The proposed solution is a $ 100 laptop, is durable and versatile can afford at a price in the third world. The fact that what has been achieved in fact avoided a remarkable achievement, the very idea of what was until recently by industry leaders as possible.

The strongest argument for this idea cheap laptop resting on the laurels of the great strengths of a person are his children, so the highest priority to the social upbringing of these children. During the illness, natural disasters, war and poverty, education is listed as the primary solution to the problem.

Most educators would say that effective learning results from a basic level of personal curiosity about a subject, and in a sense, the ability for self-learning. The essential point here is not so much that every child knows so well, it is more the view of them may have a problem. It is well known, case studies that computer learning network, complemented by technology and Internet connectivity is bearing fruit in serious academic level.

The economy is a basic laptop to $ 100 in the following: almost half of the price of buying a new laptop absorbed by the cost of sales, marketing, sales, and of course, shameless profit. In circumvention of the total retail sales and directly to governments in the absence of profit-oriented one big piece of the prize is evaporated for each model.

Physically, the most expensive aspect of the display. The use of technology at MIT, called E-Ink, which offers the potential to as low as 10 cents per square inch daylight readable clear resolution, is promising. The processor, memory and power could be disassembled, the functionality of the machine may not be so advanced about surfing, e-mail and word processing of all open source software that easily takes little resources.

It is now likely that the $ 100 laptop is going to happen. Whether it’s a good idea? While he says yes, although sociologists collect nor their arguments, it seems.

Many people are reluctant to spend money on a decent anti-virus software. I agree that about $ 50 for a decent antivirus program, it is not exactly small change. But closer look at the cost of a moment:

Computer -> $ 600 – $ 4,000
Monitor -> $ 250 – $ 1,000
Software -> $ 500 – $ 5,000
Internet connection -> $ 25 + / month
Business Privacy / -> Priceless

Thus, on the bottom of the scale we are faced with a similar investment in IT in prices like an old used car, the upper end, as a newer car used.

Maybe I am wrong, but I guess you would not buy a used car that had removed all locks and no key needed to start, and comes with a free “Steal Me sign.

Having a computer that is not an updated virus protection absolutely the same. You are just asking for trouble.

And can be found as well.

How can I be so sure? Simply because that’s what viruses, worms, malware, etc. are done. Your only job is to find unprotected computers and they attack and distract your knowledge. These things are very well what they have built, and they never stop. If your computer is not protected, and the discs, if you share online, they become infected.

The best anti-virus programs cost less than 2 months internet connection. They are all constant and keep unlimited automatic updates for your system clean and safe.

If you $ 1500 + on a computer, make $ 300 + / year on Internet connections, you can certainly pay $ 50 more than once to prevent it safe (and that they used to spread viruses and trojans on your back) .

Anything else would be barbaric!

Postscript Some people have begun to argue that if you should not have antivirus software, you will be held legally responsible if your computer is used as part of an attack (even if you do not know).

Adding Computer Memory – Some Tips

You must ensure that the laptop is turned off and no external power supply. No light should be visible, and when to stop them and check all power sources.

Laptop are a bit different from desktop, that it is not necessary to disassemble it to add memory. Access to the memory slots is via a panel is (typically) at the bottom of the laptop. Once you have found this panel, it takes very little help from a screwdriver to open the Control Panel, and look at the existing store. In fact can you do to select the type of memory your laptop uses currently reviewing, as it is normally displayed on the front of the band memory, and must be visible when you open the store.

The memory strips are usually kept in small clips on the ends of the strips. To remove the existing memory, simply return the clips and gently pull the memory strips in their location. If you are simply adding memory of course and there is space available, just add the new memory card, pushed gently to make sure it fit properly in the slots, then end clips to keep the memory in the new position.

Once you replace or add memory to your laptop, it’s simply a case of replacing the access panel, then screw the panel back in place.

Finally, turn on the laptop, and make sure that the memory was read by the laptop. When the PC starts, it takes the memory and tell you how he thinks he has access.

In case of problems, repeat the whole process very closely, that the memory is plugged into the laptop.

Of course, we probably do not want all devices on a network receive each broadcast by any other device on the network sent! Therefore, we need to know which devices can create several smaller broadcast domains. This allows us to limit emissions in order to travel on our network – and you will be surprised how much traffic there is on some networks from unnecessary emissions.

With the help of the OSI model, there are devices such as hubs and repeaters to the first layer. It is the physical layer and the equipment at this level has no effect on broadcast domains.

The layer two, we have switches and bridges. Does knowing default, a switch has no effect on broadcast domains, CCNA candidates that a change in an emission unique to each port, except the one on which it was received provided. However, it allows Cisco switches to create virtual LANs, or VLANs, the logical segments of the network. A shipment sent from a host in one VLAN will not be transferred to all other switch ports. This problem will only be transferred through the ports that members of the same VLAN as the host device has been sent.

The good news is that broadcast traffic will not be forwarded between VLANs. The bad news is that no inter-VLAN traffic by default at all is allowed! You may really want that in some cases, but usually you will have inter-VLAN traffic. This necessitates the use of a router or other Layer 3 device such as a Layer 3 switch. (Layer 3 switches are becoming popular. Basically is a switch that can also run the routing protocols. These switches are not tested on the CCNA exam.)

This router also defines broadcast domains just mentioned. Routers forward any broadcasts, so broadcast domains are defined by the routers without additional configuration.

Know-emissions journey through your network, and how it can be controlled, is an important part of being a CCNA and a director of network quality. Good luck to you in both activities!

Each disk (hard disk, floppy disk, CD, DVD) contains a boot sector, if there is a bootable floppy disk or not. If a computer is turned on, it looks for boot information. If the computer finds a disk with boot information, it reads this information and uses it well to boot. If for some reason the boot information that is infected by a virus, the virus is activated and can be transferred to the hard drive of your computer (if the infection was on a CD).

Once the boot code on the hard drive is infected the virus will have to be loaded into the memory of your computer every time you restart your computer. From memory the boot virus can be any disk that is plugged into the computer to travel. To spread the infection.

Most boot virus can cause a long time without problems, easy to spread by force there. Often, these viruses are designed to enable their bad behavior on a particular date (Halloween, for example). There are bad boot sector virus that destroy the boot information or force will enter a complete formatting the hard drive immediately after a computer.

Infectors program

When an infected application is run, the virus is activated and loaded into memory. Although the virus in memory is a new program file that you can do become infected. This means that there are more and more applications on your system that may be infected. Multiple infections are very common and certainly problems of the system.

Program files may function without problems for a while, but eventually they will have problems or multiple infection brings the entire computer system. The data of the program product may be an early sign of infection such as saving files without proper names, or incorrect / incomplete data are stored.

The viruses of this kind are often designed for programs that share information between users / computers such as e-mail applications, screen savers, macros, see Office documents, and self-extracting compressed files.

By attaching to e-mail

Most of the most dangerous viruses are primarily spread through e-mail attachments – files that are sent by e-mail can be. In these cases, the user of an infected computer without the knowledge, attaches an infected file, e-mail, the e-mail sent to a friend or colleague. If the message is received, the virus is launched when the attachment is opened, thus infecting a new computer. The e-mails with animations, automated greeting cards, jokes, photos, tables and files of documents are all documented to contain virus files.

More and more frequently these days to the mass mailing or e-mail viruses are released. These attacks automatically in files on your computer for e-mail, he can find, then use your e-mail application automatically send infected messages to any e-mail in any file on your computer (and not only the files E-mail message).

It is important to know, e-mails you open, make sure they do not contain harmful viruses. Even e-mails from friends and family can be a virus when the computer is infected person. This is an anti-virus software would be really useful to detect when an incoming virus in all messages.

Facilities Consumer Wireless
Basically we have Wireless-toys are a hit with children. But all the most common system is familiar, wireless phone without which most of us our lives we must live. Mobile phones have rapidly expanded to the output of the wired phones in a matter of a few years ago. Even cordless phones are easy with the advent of CDMA technology. 3G mobile phones can transmit up to 2 Mbit / s data.

Mobile phones have reached their zenith of glory when the Motorola satellite phones (Iridium), which need not even introduced a wireless network, but has worked directly with satellites.

Connectivity is only in theory, look what has made broadband wireless systems. Internet connectivity should not “wired” as it is, wireless broadband services. The iPod has broken the world into our pockets. What do we imagine that the year than other wireless systems is useful, wireless microphones has been overthrown by a gadget called the iPod pocket.

Wireless Gadgets

If we are in a position to the new cruise ship 50,000 “high speed can be observed, one can imagine that the” emptiness “(wireless can do) it. Take a look at some cute gadget of the raging current.

1. Push-to-talk phones: Talk, surf watch TV on the Internet, and connection to all your friends with a push button.

2. Pocket PC and wireless LAN for laptops: Pocket PC twice as mobile phones. Phones to connect to a LAN with a wireless network card.

3. Toys game controls, etc.

4. Home Cinema, Music Booster Network Systems, and the helmet, etc.

Long ago, when the gods told they are not verbally! They communicated in silence. Just where are we going?

Mobile technology is changing from day to day, that’s why this is not an easy task to find the best. They are smaller and faster than desktops. Some laptops with high quality Wireless Fidelity and many with tri-mode 802.11a/b/g wireless system coming. You can also use the latest ultra-portable Sony VAIO VGN-T350P, offers the world’s first integrated cellular modem. It can easily be connected to the Internet via mobile phone.

Company laptops can easily be carried in a briefcase, the note so that when purchasing a new you that your weight should be no embarrassment, because sometimes you must take the whole day. You can light and small laptop in the category you choose “Thin and Light” and “ultra-portable. Laptops are expensive and you can easily buy two desktop computers for the price of a laptop, but remember that you are not your desktop all day.

Some laptops offer a storage capacity of 60-100 GB hard drive, but you can increase the space with an external hard drive. The laptops are very powerful and can not be any task difficult, but generally you need 256 MB RAM for Windows XP and Mac OS X. You should also check his autonomy at the time of purchase, because it travels an important factor for a business man. Latest notebook models offer five hours or more power, but in choosing laptop battery, you should always select a battery with a higher number of cells. Note that the more cells will provide an additional battery.

You should also check security feature of the laptop. You can select one of the IBM / Sonoma ThinkPad series you can easily protect your sensitive documents and confidential company documents. Last but not least factor is price, extremely important when buying a laptop is. You can try two or more transactions for a reasonable laptop. Buy a laptop online is another option for you. You should try to negotiate a special price. Several manufacturers offer low prices when you buy in large quantities.

You do not have to sacrifice quality for a reasonable price. Try a laptop that can easily meet to buy all your needs. You should check the speed, scalability, and factors of Serious Games on the purchase of a laptop.

Always check the address in the URL to ensure that you are on a secure page. It should begin with “https” as you know, this is to start very safe. If it starts with “http”, then the page is not secure and you end up compromising your computer security when you go to the website information you give.

Viruses can spread very quickly, so if you think that your computer may be infected, you should be careful not to move at a different location on the computer or other e-mail. If your computer from the network disconnect have a good chance to isolate the damage.

Always looking for different types of e-mails from known phishing. It is a scam to get you to reveal in the provision of personal data. Once you do that, spyware can be connected to your computer. Never e-mails asking for personal information that most companies are not credible contact to respond to this information.

Make sure you buy a virus and spyware protection program that is very easy to install. Most of them offer a step by step instructions to follow you. You can easily find out how to install the software before you buy just by reading some independent reviews online.

You must own the program from your computer protection to choose very narrow. Although it is designed to bring you the best security, you can be sure those who try to viruses or spyware in your system will pass, is very intelligent. They have learned complex tricks you can access your data to.

One of the newest tactics that have used these criminals is the software that supposedly protect your computer from viruses and spyware is for sale. Unfortunately, what you sell is what you are trying to protect themselves against. Always the software from a company that has an excellent reputation not only one, you meet online for a good price.

To ensure that your computer is protected against viruses and spyware, you want a program that offers immediate updates. They usually occur during a full year after installation of the program. This will ensure that your antivirus software is always the newest and the criminals have difficulty infecting your computer systems from viruses and spyware.