watchmyip - Displays your current IP address. | ip | what is my ip | whatismyip | find ip | find your ip address | ipaddress | ipconfig | address | remote | remote access | whois | vpn | admin | dns | tcp | portscan | telnet | ping | network | router | openssh | linux | ipv6 | ipv4 | domain | host | VPS | dedicated server | whatis ip | what is ipv4 | what is ipv6 | what is host | whats is VPS

What is an IP address?

Every device connected to the public Internet is assigned a unique number known as an Internet Protocol (IP) address. IP addresses consist of four numbers separated by periods (also called a 'dotted-quad') and look something like 127.0.0.1. Since these numbers are usually assigned to internet service providers within region-based blocks, an IP address can often be used to identify the region or country from which a computer is connecting to the Internet. An IP address can sometimes be used to show the user's general location. Because the numbers may be tedious to deal with, an IP address may also be assigned to a Host name, which is sometimes easier to remember. Hostnames may be looked up to find IP addresses, and vice-versa. At one time ISPs issued one IP address to each user. These are called static IP addresses. Because there is a limited number of IP addresses and with increased usage of the internet ISPs now issue IP addresses in a dynamic fashion out of a pool of IP addresses (Using DHCP). These are referred to as dynamic IP addresses. This also limits the ability of the user to host websites, mail servers, ftp servers, etc. In addition to users connecting to the internet, with virtual hosting, a single machine can act like multiple machines (with multiple domain names and IP addresses).

What is IPv4?

Internet Protocol version four, or IPv4, is a system of addresses used to identify devices on a network. Originally described in 1981 in RFC791, IPv4 is the most widely used Internet layer protocol, and at this point is used by the vast majority of users to connect to the Internet. IPv4 addresses are actually 32-bit numbers. This means that there are 232, or just over four billion, possible addresses. Over time, however, it has become clear that more addresses than this will be required to ensure ongoing growth of the Internet. The unused pool of IPv4 addresses is predicted run out in the next two years, so an alternative is required.

What is IPv6?

Internet Protocol version six, or IPv6, is an Internet layer protocol developed in the 1990s (and described in RFC2460) as an alternative to IPv4. Rather than using a 32-bit system, IPv6 is based on 128-bit addresses, meaning that there are 2128 individual addresses available, which is approximately 3.4×1038, and exactly: 340,282,366,920,938,463,463,374,607,431,768,211,456 IPv6 provides enough addresses to allow the Internet to continue to expand and the industry to innovate. It is not, however, directly compatible with IPv4, meaning that a device connected via IPv4 cannot communicate directly with a device connected using IPv6. Deploying IPv6 on a global scale is vital to the Internet industry, but it requires pro-active steps on the part of industry players: technology must be upgraded, staff trained, business plans developed. Uptake to date has been relatively slow, but this is now changing, and businesses need to be aware of the need to adopt IPv6. To ignore IPv6 is to risk your medium to long term business viability.

What is DNS?

Domain Name System (DNS) is a database system that translates a computer's fully qualified domain name into an IP address. Networked computers use IP addresses to locate and connect to each other, but IP addresses can be difficult for people to remember. For example, on the web, it's much easier to remember the domain name www.amazon.com than it is to remember its corresponding IP address (207.171.166.48). DNS allows you to connect to another networked computer or remote service by using its user-friendly domain name rather than its numerical IP address. Conversely, Reverse DNS (rDNS) translates an IP address into a domain name. Each organization that maintains a computer network will have at least one server handling DNS queries. That server, called a name server, will hold a list of all the IP addresses within its network, plus a cache of IP addresses for recently accessed computers outside the network. Each computer on each network needs to know the location of only one name server. When your computer requests an IP address, one of three things happens, depending on whether or not the requested IP address is within your local network:

If the requested IP address is registered locally (i.e., it's within your organization's network), you'll receive a response directly from one of the local name servers listed in your workstation configuration. In this case, there usually is little or no wait for a response.
If the requested IP address is not registered locally (i.e., outside your organization's network), but someone within your organization has recently requested the same IP address, then the local name server will retrieve the IP address from its cache. Again, there should be little or no wait for a response.
If the requested IP address is not registered locally, and you are the first person to request information about this system in a certain period of time (ranging from 12 hours to one week), then the local name server will perform a search on behalf of your workstation. This search may involve querying two or more other name servers at potentially very remote locations. These queries can take anywhere from a second or two up to a minute (depending on how well connected you are to the remote network and how many intermediate name servers must be contacted). Sometimes, due to the lightweight protocol used for DNS, you may not receive a response. In these cases, your workstation or client software may continue to repeat the query until a response is received, or you may receive an error message.

When you use an application such as telnet to connect to another computer, you most likely type in the domain name rather than the IP address of that computer. The telnet application takes the domain name and uses one of the above methods to retrieve its corresponding IP address from the name server. A good analogy is to think of DNS as an electronic telephone book for a computer network. If you know the name of the computer in question, the name server will look up its IP address.

What is a MAC address?

Short for Media Access Control address, a hardware address that uniquely identifies each node of a network. In IEEE 802 networks, the Data Link Control (DLC) layer of the OSI Reference Model is divided into two sub-layers: the Logical Link Control (LLC) layer and the Media Access Control (MAC) layer. The MAC layer interfaces directly with the network medium. Consequently, each different type of network medium requires a different MAC layer. On networks that do not conform to the IEEE 802 standards but do conform to the OSI Reference Model, the node address is called the Data Link Control (DLC) address.

What is a Dedicated Server?

A dedicated server is a single computer in a network reserved for serving the needs of the network. For example, some networks require that one computer be set aside to manage communications between all the other computers. A dedicated server could also be a computer that manages printer resources. Note, however, that not all servers are dedicated. In some networks, it is possible for a computer to act as a server and perform other functions as well. In the Web hosting business, a dedicated server is typically a rented service. The user rents the server, software and an Internet connection from the Web host.

What is a VPS?

VPS stands for "Virtual Private Server". It is a type of hosting where you share a physical server with other customers, but are allocated a dedicated share of system resources. VPS plans are a good stepping stone between cheap shared hosting and more expensive dedicated hosting. Some VPS hosting plans give you complete (or "root") control of the server -- giving techies the benefits of a dedicated server without the high cost. You can also find plans where the hosting company takes care of all the technical details -- giving non-technical business owners the ease of shared hosting and the peace of mind of dedicated resources. This service is commonly referred to as "fully managed" hosting.

What is a host / hostname?

A host name is a name that is assigned to a host that uniquely identifies it on a network and thus allows it to be addressed without using its full IP address. A host is a computer that is connected to a network, usually the Internet or other TCP/IP (transmission control protocol/Internet protocol) network, such as a LAN (local area network). Each host on a TCP/IP network has a unique IP address, which is a unique numeric identifier. Host names are very useful because it is much easier for humans to remember them than to remember IP addresses, which can contain as many as 12 digits under the currently mainstream IPv4 addressing scheme (or as many as 32 hexadecimal digits under the next-generation IPv6 addressing scheme). Moreover, it is a simple matter for system administrators to assign host names on a LAN or other private network. Host names on smaller networks typically consist of a single word (or words) that describe the host and omit the domain name. A domain name is a name that uniquely identifies a host on the Internet. For example, some of the computers in the accounting department of a small business might be assigned host names such as accounting1, accounting2 and accounting3. Each host typically has a single host name. However, hosts are also allowed to have multiple host names.

What is a Domain name?

Domain names are used to identify one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. For example, in the URL http://www.pcwebopedia.com/index.html, the domain name is pcwebopedia.com. Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. There are only a limited number of such domains. For example:

gov - Government agencies

edu - Educational institutions

org - Organizations (nonprofit)

mil - Military

com - commercial business

net - Network organizations

ca - Canada

... - ...

Because the Internet is based on IP addresses, not domain names, every Web server requires a Domain Name System (DNS) server to translate domain names into IP addresses.

What is FTP?

Short for File Transfer Protocol, the protocol for exchanging files over the Internet. FTP works in the same way as HTTP for transferring Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet's TCP/IP protocols to enable data transfer. FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).

What is a Proxy server?

A server that sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server. Proxy servers have two main purposes:

Improve Performance: Proxy servers can dramatically improve performance for groups of users. This is because it saves the results of all requests for a certain amount of time. Consider the case where both user X and user Y access the World Wide Web through a proxy server. First user X requests a certain Web page, which we'll call Page 1. Sometime later, user Y requests the same page. Instead of forwarding the request to the Web server where Page 1 resides, which can be a time-consuming operation, the proxy server simply returns the Page 1 that it already fetched for user X. Since the proxy server is often on the same network as the user, this is a much faster operation. Real proxy servers support hundreds or thousands of users. The major online services such as America Online, MSN and Yahoo, for example, employ an array of proxy servers.

Filter Requests: Proxy servers can also be used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites.

What is VPN?

(pronounced as separate letters) Short for virtual private network, a network that is constructed by using public wires to connect nodes. For example, there are a number of systems that enable you to create networks using the Internet as the medium for transporting data. These systems use encryption and other security mechanisms to ensure that only authorized users can access the network and that the data cannot be intercepted.