What are the security problems faced by a network?

Making mistakes concerning the network security is very common. The same mistakes are repeated again and again. These problems cannot be solved without changing our working methods. In this article we discuss about some common security problems that are faced by a network.

ØUsing weak and non-complex passwords for accessing the network: 

- Brute forcing is an old school exploit to which many of the system network administrators are open to. 

- The very famous captcha technology has been implemented for correcting this vulnerability of the network security passwords. 

- In the common captcha, the user is required to type in the digits or the letters that are displayed on the screen in some sort of distorted image. 

- This technology has been designed to prevent the network to be accessed by unwanted internet bots.

- However, this is not as safe as it looks. 

- It just gives a false sense to the network admins for countering the brute forcing. 

- Complex password is the solution for this problem. 

- For creating a complex password, more than seven characters need to be combined with special characters and numbers. 

- Apart from the creation of the complex passwords, a password expiration system has to be implemented. 

- This system is for reminding the users for changing their passwords. 

- Also, care should be taken regarding the reuse of the passwords. 

- Cycling of the passwords should not be allowed.

Ø Using server application or software that is outdated: 

- The patches are released by the companies from time to time for ensuring that the system does not become vulnerable to the various threats. 

- Also, new exploits and threats are posed by the hackers that can harm the network if the patches are not properly used. 

- For ensuring the network administrator is kept informed of the new threats, the software or the applications have to be updated regularly.  

Ø Web cookies: 

- Even though the viruses and malware cannot be introduced in to the network through cookies, these cookies can be tracked by some third party cookies for compiling the records of the browsing histories of the individuals. 

- The cookies that are not encrypted pose a major threat because they make the system vulnerable to the cross site scripting (XSS) attacks, thus putting your privacy at risk. 

- The open cookies can provide access to the cookies with the log-in data which can be used by hackers for intruding in to your systems. 

- The solution to this problem is to use the encrypted cookies along with an encoded expiration time. 

- The admins might ask the users to re-log-in before accessing important network directories.

Ø Plain hashes: 

- Hashing is the technique used for indexing and retrieval purposes in the database. 

- In most of the encryption algorithms, the plain hashes are mostly used. 

- A type of encryption is the salt that might be added to the hashes for making the creation of a look-up table that might assist the brute force or directory attacks extremely difficult or let’s say almost impractical. 

- But this works only when large salt is used. 

- Usually a pre-computed look up table might not be used by the attacker in exploitation of the network. 

- This makes the network security system even more complex.

- So even if the attacker is able to break into your system, he won’t be able to access the information from the database. 

- The encryption key should be kept hidden.

Ø Shared web hosting: 

- This service is used by the websites that reside on one same server. 

- Each site is given its own partition. 

- This is economically feasible for most of the systems. 

- But here if the attacker breaches in to system of one website, he can get into other website’s security systems too. 

What are transport and application gateways?

- Hosts and routers are separated in TCP/IP architecture. 

- For private networks, more protection is required to maintain an access control over it. 

- Firewall is one of the components of this TCP/IP architecture. 

- Internet is separated from Intranet by this firewall.

- This means all the incoming traffic must pass through this firewall. 

- The traffic that is authorized is allowed to pass through. 

- It is not possible penetrate the firewall simply. 

Firewall has two components namely:

Ø  Filtering router and

Ø  Two types of gateways namely application and transport gateways.

- All the packets are checked by the router and filtered based up on any of the attributes such as protocol type, port numbers, and TCP header and so on. 

- Designing the rules for filtering of the packets is quite a complex task. 

- A little protection is offered by this packet filtering since with the filtering rules on one side, it is difficult to cater to the services of the users on other side.

About Application Gateways

- Application layer gateways consist of 7 layer intermediate system designed mainly for the access control. 

- However, these gateways are not commonly used in the TCP/ IP architecture. 

- These gateways might be used sometimes for solving some inter-networking issues. 

- The application gateways follow a proxy principle for supporting the authentication, restrictions on access controls, encryption and so on. 

- Consider two users A and B. 

- A generates an HTTP request which is first sent to the application layer gateway rather than being send to its destination. 

- The gateway checks about the authorization of this request and performs encryption. 

- After the request has been authorized, it is sent to user B from the gateway just at it would have been sent by A.

- B responds back with a MIME header and data which might be de-crypted or rejected by the gateway.

- If the gateway accepts, it is sent to A as if from B. 

- These gateways are designed for all the protocols of application level.

About Transport Gateways

- The working of the transport gateway is similar to application gateway but it works at the TCP connection level. 

- These gateways are not dependent up on the application code but they do need client software so as to maintain awareness about the gateway. 

- Transport gateways are intermediate systems at layer 4. 

- An example is the SOCKS gateways. 

- IETF has defined it as a standard transport gateway.

- Again, consider two clients A and B. 

- A TCP connection is opened by A to the gateway. 

- The SOCKS server port is nothing but the destination port. 

- A sends a request to this port for opening the connection to B indicating the port number of the destination. 

- After checking the request, the request for connection from A is either accepted or rejected. 

- If accepted, a new connection is opened to B. 

- The server also informs A that the connection has been established successfully. 

- The data relay between the clients is kept transparent. 

- But in actual there are two TCP connections having their own sequence numbers as well as acknowledgements. 

- The transport gateways are simpler when compared with the application layer gateways. 

- This is so because the transport gateways are not concerned with the data units at the application layer. 

- It has to act on the packets simply once the connection has been established. 

- Also, this is the reason why it also gives higher performance in comparison with the application layer gateways. 

- But it is important that the client must be aware of its presence since there is no transparency here. 

- If between the two networks the only border existing is the application gateway, it alone can act as the firewall. 

What are multi-protocol routers?

- There are routers that have the capability to route a number of protocols at the same time. 

- These routers are popularly known as the multi-protocol routers. 

- There are situations in networking where combinations of various protocols such as the appletalk, IP, IPX etc. are used. 

- In such situations normal typical router cannot help. This is where we use the multi-protocol routers. 

- Using the multi-protocol routers, information can be shared between the networks. 

- The multi-protocol router maintains an individual routing table for each of the protocols.

- The multi-protocol routers have to be used carefully since they cause an increase in the number of routing tables that are present on the network. 

- Each protocol is advertised individually by the router. 

A multiprotocol router consists of the following information:

Ø  Routing information protocol (RIP)

Ø  Boot protocol relay agent (BOOTP)

Ø  RIP for IPX

- The multi-protocol routers use this routing information protocol for performing dynamic exchange of the routing info. 

- Routers using RIP protocol can dynamically exchange information with the other routers that use the same protocol. 

- The BOOTP agent is included so that the DHCP requests can be forwarded to their respective servers residing on other subnets. 

- It is because of this, a single DHCP server can process a number of IP subnets. 

- Multi-protocol routers do not require to be manually configured.

- The networking world these days relies totally up on the internet protocol. But there are certain situations where certain tasks can be performed more efficiently by the other protocols. 

- Most of the network protocols share many similarities rather than being different. 

- Therefore, if one protocol can be routed by a protocol efficient, then it is obvious that it can route the other one also efficiently. 

- If we route the non-IP protocols in a network, this implies that the same staff that takes care of the IP monitoring is administering the non-IP routing also. 

- This reduces the need for more equipment and effort. 

- There are a number of non-IP protocols available using which a LAN can work more effectively. 

- Using a number of non-IP protocols, a network can be made very flexible and easier to meet the demands of its users. 

- All these points speak in the favor of multi-protocol routing in an abstract way. 

- But the non-IP protocols to be routed must be selected with care. 

Below we mention reasons why routing non – IP protocols can be avoided:

1. It requires additional knowledge because you cannot master everything. For individual protocol an expert is required who in case of a failure can diagnose it and fix it.
2. It puts extra load on the routers. For every protocol, the router would have to maintain a separate routing table. This calls for a dynamic routing protocol for the router itself. For all this, more memory is required along with high processing power.
3. It increases the complexity. Multi-protocol router even though it seems to be simple, it is quite a complicated thing in terms of both hardware and software. Any problem in the implementation of the protocol can have a negative impact up on the stability of all the protocols.
4. Difficulty in designing: There are separate rules for routing of each protocol, assignment of the addresses and so on. There are possibilities that there might be conflicts between these rules which means it is very difficult to design.
5. It decreases stability. Scaling capacity of certain protocols is not as good as of the others. Some of the protocols are not suited to work in a WAN environment. 

What is the difference between TCP and UDP?

TCP (transmission control protocol) and UDP (user datagram protocol) are two very important protocols. These two protocols are transportation protocol.  These two protocols are counted in the core protocols of the IP suite. 

These two protocols operate at the 4^th layer i.e., the transport layer of the TCP/ IP model but the usage of the both the protocols is used very differently.

1. Reliability: 

- UDP is a connection-less protocol whereas TCP is a protocol that is connection  oriented. 

- Whenever a message is sent, it will not get delivered if there is a connection failure. 

- If during the delivery of the message the connection gets lost, the server will send a request to get the lost part. 

- During the transfer of a message, there is no corruption. 

- The reliability of the UDP is less and if a message is sent, there is no guarantee that it will get delivered, it may get lost on the way. 

- The message might get corrupted during transfer.

2. Ordered: 

- If at the same time two messages are sent along the same connection, one after the other, it is sure that the message which is the first in the line will get delivered there first. 

- The data is therefore delivered always in the same order. 

- You do not have to worry about the order of the arriving data. 

- In the case of UDP, the order of the arrival of data is not sure. 

- The second one can arrive there first before the first one. 

3. Heavyweight: 

- When the order of arrival of the low level parts of the transmission stream is wrong, the requests have to be sent again and again. 

- All the lost parts of the message have to be put together in a proper sequence. 

- So it takes some time for putting back the parts together. 

- On the other hand, UDP is lightweight.

- After sending the message, the user cannot think about tracking connections or ordering of the messages etc. 

- This indeed makes it lot quicker and therefore there is very less work for the network or the OS card for translating the data obtained from the data packets.

4. Streaming: 

- In TCP, the data is read in form of a stream.

- There is nothing that distinguishes one data from another. 

- Per read call there can be a number of packets. 

- In UDP each of the data packets is sent individually and if they arrive, they do so in whole form. 

- Here per read call, only one packet is sent.

5. Some examples of the TCP are FTP or file transfer protocol, World Wide Web (such as Apache TCP port 80), secure shell such as open SSH port 22 and so on. Examples of UDP are TFTP (trivial file transfer protocol), VoIP (voice over IP), IPTV, online multiplayer games, domain name system (such as DNS UDP port 53) etc.

6. Error-checking: 

- The TCP protocol offers extensive error checking mechanisms for the acknowledgement of the data, flow control and so on. 

In TCP, a connection is a must to be established in order to transfer data. Datagram mode is the mode in which the user data gram protocol operates. You can choose between the two protocols depending up on the requirements. If the guaranteed delivery of data is required, then the transmission control protocol must be chosen. The user data gram protocol comes only with the basic error checking mechanism. It checks the data by the means of the check sums. 

What are different types of operating system?

Developing an operating system is one of the most complicated activities and favorite of most of the computing hobbyists. For a hobby OS, its code is not directly derived from the already existing Oss. Some entirely new concepts might also be included in the OS development. It may also start from modeling an existing one. Whatever the case maybe, the hobbyist is his own active developer. Application software might be developed specifically for an OS or hardware. Therefore, when the application has to be ported to some OS that may implement its required functionality differently, the application might be required to be changed, adapted or maintained. 

Types of Operating System

There are many types of operating about which we shall discuss in this article.

1. Real time operating system: 

- It is a multi – tasking OS aimed at the execution of the applications that are real time. 

-These operating systems work on scheduling algorithms written exclusively for them. 

- This is done so as to make them achieve a behavior that is deterministic in nature. 

- Their main objective is to give a quick response to the events that is also predictable in nature. 

- The design which is implemented is event driven and employs the idea of time sharing and sometimes both. 

- The system that is event driven switches among the different tasks according to the priorities assigned to them. 

- On the other hand, the systems following the time sharing methodology switch between the tasks based up on the clock interrupts.

2. Multi–user and single user operating systems: 

- In the multi–user operating systems the same computer system can be accessed by multiple users at the same time. 

- Systems that can be classified under the multi–user systems are the internet servers and the time sharing systems since using the time sharing principle they allow multiple users to access the system. 

- There are other types of operating systems that allow only one user to execute a number of programs simultaneously and are called the single – user operating systems.

3. Multi–tasking and single–tasking operating systems: 

- The operating systems that allow multiple programs to be executed simultaneously (as per the human time scales) are termed as the multi – tasking OS.

- In the single–taking OS, only one program can be run at a time. 

- Multi –taking can be done in the following two ways:

Ø  Pre–emptive multi –tasking: The CPU time is sliced and each of the time slots are given to each of the programs that are to be executed. This kind of multi–tasking is supported by the operating systems such as Linux, AmigaOS and Solaris.

Ø  Co–operative multi–tasking: Systems following this rely on one process for giving time to the other processors but in a pre–defined manner. This multi–tasking type was used by the MS windows 16 – bit version, Mac OS preceding OS X.

There are Oss that used to support both of these namely win9x and Windows NT.

4. Distributed operating system: 

- This kind of OS is used to manage a group of computers that are independent of each other and makes them seem like one single system.

- This OS led to the development of networked computers which could link to and communicated with one another.

- These computers in turn paved way for distributed computing. 

- They carried out computations on more than one computer. 

- Computers working in cooperation with each other, together make up a distributed system.

5. Embedded Operating System: 

It is used in embedded computer systems such as in PDAs.

What is an Operating System?

- A collection of small and large software that help in the management of the computer hardware resources is called an operating system. 

- As the term suggests it operates or drives the system. 

- The basic common services required by the computer programs are offered by this OS only. 

- Without an OS, the application programs would fail to function. 

- Operating systems are of many types. 

- One such type is the time sharing OS that schedules the tasks to be done so that the processor time, printing, mass storage and so on resources could be utilized efficiently. 

- It is an intermediate thing between the hardware and the user. 

- It is through the OS that you are able to actually communicate with the computer hardware. 

- Functions such as memory allocation and basic input output operations are dependent totally on the OS. 

- Even though the hardware directly executes the application code, it does frequently involve the OS or OS itself interrupts in between. 

- Any device containing a computer do has an OS such as video game consoles, mobile phones, web servers, super computers and so on.

- Some popular OS are:

Ø  Android

Ø  BSD

Ø  Linux

Ø  iOS

Ø  Microsoft windows

Ø  Windows phone

Ø  Mac OS X

Ø  IBM z/ OS

All the OS have relation with UNIX save windows and z/OS.

- Types of Operating systems are:

1. Real time OS
2. Multi – user OS
3. Multi – tasking OS
4. Single  - tasking OS
5. Distributed OS
6. Embedded OS

- It was in 1950 that the basic operating systems came in to existence such as parallel processing, interrupts and run time libraries.

- Assembly language was used for writing the UNIX OS. 

- There are many sub–categories in the Unix like family of the operating systems:

1. System V
2. BSD
3. Linux and so on.

- A number of computer architectures are supported by these Unix – like systems. 

- They come in heavy use in the following fields:

1. Servers in business
2. Work stations in academic
3. Engineering environments

- Few UNIX variants are available for free such as BSD, Linux etc. and are quite popular. 

- The holder of the Unix trademark is the open group and it has certified four Oss as Unix so far. 

- Two of the original system V Unix descendants are IBM’s AIX and HP’s HP – UX and they run only on the hardware provided by their manufacturer. 

- Opposite to these is the sun microsystem’s Solaris OS that can be used on different hardware types (inclusive of the Sparc and x86 servers etc. and PCs). - The POSIX standard was established to the sought the inter-operability of the Unix. 

- This standard is applicable for any OS now, even though originally it was developed especially for the variants of Unix.

- Berkeley Software Distribution or BSD family is a Unix sub–group. 

- It includes the following:

1. FreeBSD
2. NetBSD
3. OpenBSD

- The major use of all of these is in the web servers. 

- Furthermore, they are also capable of functioning as a PC OS. 

- BSD has made a great contribution in the existence of the internet. 

- Most of the protocols were refined and implemented in BSD. 

What is meant by Dynamic Virtual Private Network?

Dynamic virtual private network or DVPN is a network used for interconnecting various virtual application networks. 

- These networks reduce the need for manual configuration by a large percentage (almost by 93 %). 

- Dynamic virtual private networks help a great deal in the simplification of the wide area connectivity spread across a virtual application network.

- These networks have a great complexity when compared to the other networks.

- Further, they prove useful in establishing interconnections between various campuses, data centers, and offices and so on via IPsec VPN encryption. 

- The solution offered by the DVPNs is quite scalable, simple and secure. 

- The dynamic virtual private networks are highly automated and therefore provide a simple management solution. 

- A DVPN can scale up to 1000 – 3000 sites on a single router. 

- All these sites together constitute the domain of the DVPN. 

- So it is obvious that a very large network can be scaled via multiple DVPNs. 

- The best thing about these DVPNs is that they support all the WAN technologies and therefore can be implemented up on all.

- Furthermore, they offer flexibility in reducing the cost when compared to the lower cost broadband access.

- All the network operations are simplified since DVPN has automated VPN setup plus provisioning.

- DVPNs offer high resilience without adding to the complexity of the network. 

- Another characteristic feature of a dynamic virtual private network is its carrier agnostic connectivity.

- One solution to DVPN is offered by HP that has got the following features:

1. Full mesh or hub – spoke configuration
2. Encryption based up on IPsec standards.
3. The control plane and the data plane have been separated to ensure scalability.
4. Up to 30,000 clients are supportable by the VAM (VPN address management) server.
5. Offers zero touch configuration.

- Another solution is offered by the Juniper networks. 

- Juniper’s DVPN is more of a client-less solution and has been designed for ‘remote access’ IPsec VPN. 

- The delivery of the client to the end users is made dynamically from SRX. 

- The remote access is simplified by DVPN since it provides the users the facility to secure the IPsec VPN tunnels without any need for configuring the VPN settings on their systems. 

- This whole process comes in to when the users login to the server’s web site. - Juniper’s DVPN solution can be licensed to 5, 10, 25 or 50 concurrent users. 

- It supports windows xp and above versions (both 32 and 64 bit).

- However, there are certain limitations for this solution:

1. It requires an external RADIUS server for providing an IP address and for XAUTH.
2. Does not support shared IKE id.
3. Mandatory PFS (perfect forward secretary).
4. Requires custom IKE/ IPsec security proposals.
5. Only IKE – id supported is the FQDN.

- Configuration for DVPN is required only on the SRX gateway.

- Dynamic virtual private network is more of an intranet enabler whose purpose is to complement the regular services offered by the internet by adding more services as well as resources to it. 

- One major feature of these networks is that they have an excellent ability of loading balance on – the – fly allocation of the resources. 

- These networks are more popular in businesses since they offer more security by means of packet encryption protocols. 

- Self – modification is possible for the DVPNs and so they are able to recognize the added nodes without help from routers.

- Encryption and authentication are two technologies used by DVPNs for securing packing data and delivering across the networks. 

- Until the data reaches it destination it remains unpacked or encapsulated. 

- For reaching the remote networks tunneling is used. 

What are the features of Telerik Test Studio?

About Telerik Test Studio

- Telerik test studio is a software testing tool that has been developed for carrying out different  kinds of testing such as the functional testing for web and desktop applications, performance testing, mobile application testing and load testing etc. 

- Telerik developed it to suit all kinds of web and desktop applications eliminating the need for writing the code.

- This testing tool lets you build easy collaboration between the QA professionals and the software developers. 

- The tool has been built in such a way so as to support several web technologies such as the HTML, Silverlight, javascript, asp.net and ajax. 

Features of Telerik Test Studio

1. The test recording in test studio does not depend on the scripts.
2. It supports cross – browser testing for a number of browsers such as Mozilla Firefox, Chrome, Internet explorer and safari.
3. Application testing is supported for applications developed in HTML, Silverlight, asp.net MVC and ajax.
4. It supports the web element abstraction and focuses on reusing them.
5. The test studio can be integrated with the 2008 and 2010 editions of the visual studio.
6. The tool can be integrated with the Nunit, Xunit and MbUnit.
7. The test studio validates the user interface based up on the sentences.
8. It has got a visual storyboard that lets the team members know about the progress done so far.
9. It supports the customization of the test in vb.net and C#.
10. It can also be used to carry out exploratory testing.
11. Telerik test studio can be integrated with the HP quality center.
12. It can also be integrated with the Telerik Team pulse.

- In other words, Telerik test studio provides one simple solution for most of the testing needs. 

- A special version of the test studio called the test studio for iOS has been developed using which the developers can create tests for apple products. 

- Using this tool, the developers can carry out the testing directly on the device. 

- Here, the element detection is not based up on image.

- Instead, object based recording is used.

- It supports development platforms such as the monotouch, Xcode and phonegap.

- One can test both the native and hybrid apps.

- For creating load tests you can either capture them or use the fiddler logs.

- You can run the functional tests as the performance tests and gather data regarding the client rendering time, network latency and server processing time.

- It is quite easy to get started with and quite easy to use too. 

- To create even the most complex functional, performance and load tests what that it all takes is navigation, pointing and clicking. 

- The test studio further helps in streamlining the teamwork by providing a common platform on which the developers and testers can work together. 

- Another thing about telerik test studio, it fits any budget since in one software testing tool you get the both performance and functional testing tools. 

- The license of this tool is quite affordable and can be easily obtained. 

- Some other features of test studio are:

1. Lightswitch – powered apps automation
2. Multi – browser support
3. Manual testing
4. Telerik controls automation
5. Provides native support for the kendo UI widgets
6. Data – driven testing
7. Support for browser dialog and html popups
8. Support for frames and frame sets
9. Historical view of the tests
10. Test customization
11. Single virtual user license type
12. Reporting dashboard
13. GUI test recorder
14. Visual studio professional and team system integration
15. Simple interface
16. Built – in data grid
17. Code-less conditional logic support