All About Internet Advertising Methods

People opt for internet advertising methods because practically half of the world’s population knows HTML. If you have your own business, you have to decide on what internet advertising method works for you. Ask yourself what are you going to avail of: the expensive internet advertising methods or the cheap ones? Others will pipe in “expensive!” immediately, but they don’t know cheap internet advertising method attracts great benefits as well. Continue reading “All About Internet Advertising Methods”

How can I report a person attempting to hack me?

There are a number of laws regarding hacking a computer you don’t have authorization to hack, the CFAA in the USA, the CMA in Great Britain, the CHM in Australia, and the list goes on. All of which make it illegal to do what you want to do, and in some cases have pretty strict penalties for even the smallest of actions.

The term most often used to describe what you’re talking about is Hacking Back. It’s part of the Offensive Countermeasures movement that’s gaining traction lately. Some really smart people are putting their heart and soul into figuring out how we, as an industry, should be doing this. There are lots of things you can do, but unless you’re a nation-state, or have orders and a contract from a nation-state your options are severely limited.

There’s always an “Abuse” email address on the whois of a netblock for reporting misuse of an IP address.

You can use http://whois.domaintools.com/ to do a whois lookup to get the address.

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If you are using WordPress, use Wordfence! They are really good!

Continue reading “How can I report a person attempting to hack me?”

The Mystery behind Domain Names

There are approximately 296 million .COM domains registered. That’s a lot of domain names out on the Internet that are either already taken or just parked in some obsolete spot gathering dust and all kinds of age. The most common names like loser.com. Jamesbrown.com are already taken by net investors who resell the rights to the names. Can you imagine someone having http://www.elvis.com ? He’s just waiting on the highest bidder!

There are 900 possible combinations for two letter sequences. If you’re looking for “ET” then you just won’t find it! Even allowing for digits, again every single web address is taken. Of course, that’s ignoring the fact that .COM registrars now mandate a 3-character minimum length, so it wouldn’t be an option.

Continue reading “The Mystery behind Domain Names”

The Client/Server Model

global-search-icon-1By definition, every TCP/IP application is a client/server application. In this scenario the client makes requests of a server. That request flows down the TCP/IP protocol stack, across the network, and up the stack on the destination host. Whether the server exists on the same host, another host of the same LAN, or on a host located on another network, the information always flows through the protocol stack.

From the information presented to this point, the client/server model has some general characteristics:

  • The server provides services and the client consumes services.
  • The relationship between the client and the server is machine-independent.
  • A server services many clients and regulates their access to resources.
  • The client and server can exist on different hardware platforms.
  • The exchange between client and server is a message-based interaction.
  • The server’s methodology is not important to the client.
  • The client carries the bulk of the processing workload so that the server is free to serve a large number of clients.
  • The server becomes a client to another server when it needs information beyond that which it manages.

By specifying only the interface between the Application layer and the Transport layer, the TCP/IP Application layer permits various Application layer models. This open-ended approach to the Application layer makes it difficult to draw a single model that illustrates all TCP/IP applications. On one end of the scale, applications run as shell-level commands; on the other, applications run in various window environments. For example, the traditional telnet is run from the shell. Yet, some implementations of the telnet client take advantage of windows technology. To make life more complicated, telnet implementations are also available for the distributed computing environment (DCE). C++ client/server applications use the Object Management Group’s (OMG) Common Object Request Broker Architecture (CORBA) model. Consequently, trying to define a universal Application layer model is an exercise in futility.

However, even with all the variations, the Web browser continues to grow as a popular Windows environment for the implementation of the client side of the equation.

 

Applications, Plug-Ins, and Applets

Not too long ago, programmers developed applications; now they develop applications, plug-ins, and applets. Although a program is a program, the name attached to it tells us something about the nature of the program. Alas, there are more gray zones than black and white ones. In spite of this overlap, some well-defined characteristics separate applications, plug-ins, and applets.

Starting with an application, the common characteristics are that:

  • It is a standalone program.
  • A desktop program, including Web browsers, invokes an application in a separate window.
  • An application normally implements a specific application protocol such as FTP, telnet, or SMTP.

On the other hand, a plug-in’s characteristics are that:

  • It represents an extension to a Web browser.
  • It implements a specific MIME type in an HTML document.
  • It normally operates within the browser window.

And then we have the Java applet. Is it a “small application,” or is it something else? A Java applet

  • Is written in the Java language and compiled by a Java compiler
  • Can be included in an HTML document
  • Is downloaded and executed when the HTML document is viewed
  • Requires the Java runtime to execute

Whereas applications and plug-ins must be ported to each hardware platform, applets run on any platform that has a Java runtime. Thus, applets provide an object-oriented, multiplatform environment for the development of applications.

IP Addresses and Domain Names

Internetworking routes IP datagrams according to the IP address, but humans find names easier to remember. This section briefly reviews the principles of IP addresses and provides an overview of how names are resolved to addresses.

What Is an IP Address?

Perhaps the easiest way to understand IP addresses is to look at the Internet as a global network. All networks that comprise the global network are just subnets. InterNIC provides the first level of subnetworking by dividing the global address space into classes that are assigned to organizations. The organizations are then responsible for subdividing their assigned address space to meet their network needs.

Figure 1.18 : IP addresses and subnet masks.
Figure 1.18 : IP addresses and subnet masks.

The IP address is a 32-bit number. To simplify the notation of addresses, divide this number into four octets and write the octets in a dotted-decimal format. Three types of IP addresses exist: network address, host address, and broadcast address. Because every host is part of a network, you divide the IP address into a network portion and a local host portion. When the local host portion is all zeros, it is a network address; all ones is a broadcast address. Anything else is a host address. However, the IP address itself contains no information about what constitutes the network portion versus the local host portion. The subnet mask provides this information. By convention, binary ones define the network portion, and zeros define the local host portion. Again, by convention, the ones must be contiguous to the left, and the remainder is zeros.

As mentioned previously, InterNIC splits the global address space into classes and then assigns the network address according to these divisions. Table 1.1 shows the breakdown of the address space.

 

Table Class Network Address Subnet Mask No. of Networks
table A 1-126 255.0.0.0 126
table B 128-191 255.255.0.0 16,384
table C 192-223 255.255.255.0 2,097,152
table D 224-254 255.255.255.0 (experimental)

 

As mentioned before, the designations shown in Table 1.1 represent assigned network addresses. The network manager for an organization is then responsible for additional subnetting, according to the requirements of their individual networks.

Special IP Addresses

Several special IP addresses also exist. For an Internet programmer, the most important special addresses are the local loopback address and the broadcast address. For the network administrator, the most important special addresses are those set aside for networks not connected to the Internet.

The local loopback address (127.0.0.1) enables a client application to address a server on the same machine without knowing the address of the host. This address is often called the local host address. In terms of the TCP/IP protocol stack, the flow of information goes to the Network layer, where the IP protocol routes it back up through the stack. This procedure hides the distinction between local and remote connections.

Broadcast addresses enable an application to send a datagram to more than one host. The special address 255.255.255.255 sends a “limited broadcast” to all hosts on this network. A “direct broadcast” uses the address form A.255.255.255B.B.255.255, or C.C.C.255 to send messages to all hosts on a particular class A, B, or C network. Finally, a broadcast to a particular subnet is to the address with all local host bits set to one.

RFC 1918 specifies an Internet “best current practice” for address allocation on private internets (intranets). For a network not connected to the Internet, or a network where all Internet traffic passes through a proxy server, the Internet Assigned Numbers Authority (IANA) reserved three blocks of IP address space: 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255, and 192.168.0.0 to 192.168.255.255. This block is equivalent to one class A address, 16 class B addresses, and 256 class C addresses.

Resolving Names to Addresses

In the early days of ARPAnet, a system resolved names to addresses using the hosts file. The Stanford Research International (SRI) maintained the hosts file, and each site periodically downloaded an updated copy of the file. As the number of sites connected to ARPAnet increased, this method proved too hard to maintain and placed an increasing burden on the network. In 1984 Paul Mockapetris, of University of Southern California’s Information Sciences Institute, released RFCs (882 and 883) that describe the domain name system. Today, DNS is the standard for resolving names to addresses. However, the hosts file still plays a role in name resolution during the booting of a system and as a means to provide LAN resolution when DNS is down.

f1-19
Figure 1.19 : The hierarchical structure of DNS.

In a nutshell, DNS is a distributed database whose structure looks like the UNIX file system. DNS is a client/server system in which the resolvers query name servers to find an address record for a domain name. The query process begins with the root name servers. If the root name server does not know the answer, it returns the address of a name server that knows more details about the domain name. The resolver then queries the new name server. This iterative process continues until a name server responds with the address for the domain name.

The resolver maintains the retrieved information in a cache until the designated time to live (TTL) for the record expires. This approach reduces the number of queries and, at the same time, responds to the dynamic nature of networks. By distributing the database across the Internet, the site responsible for the information maintains the information.