What is an IP Address
Content
What is an IP address?
An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.[1] An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."[2] The designers of the Internet Protocol defined an IP address as a 32-bit number[1] and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995,[3] standardized as RFC 2460 in 1998,[4] and is being deployed worldwide since the mid-2000s. IP addresses are binary numbers, but they are usually stored in text files and displayed in humanreadable notations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6). The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally and delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries (Internet service providers) and other entities. Dynamic IP addresses are temporary and are assigned each time a computer accesses the Internet. They are, in effect, borrowed from a pool of IP addresses that are shared among various computers. Since a limited number of static IP addresses are available, many ISPs reserve a portion of their assigned addresses for sharing among their subscribers in this way. This lowers costs and allows them to service far more subscribers than they otherwise could. Static IP addresses are generally preferable for such uses as VOIP (Voice over Internet Protocol), online gaming, or any other purpose where users need to make it easy for other computers to locate and connect to them. Easy access can also be facilitated when using a dynamic IP address through the use of a dynamic DNS service, which enables other computers to find you even though you may be using a temporary, one-time IP address. This often entails an extra charge, however, so check with your ISP. Static IP addresses are considered somewhat less secure than dynamic IP addresses, since they are easier to track for data mining purposes. However, following safe Internet practices can help mitigate this potential problem and keep your computer secure no matter what type of IP address you use. What is an IP Address? "An identifier for a computer or device on a TCP/IP network" as defined by Webopedia. In simple terms, its a number that consists of four numbers, separated by periods, that can be between 0 and 255. This number identifies the device (e.g. comptuer) that is connected to the
Internet, which is a TCP/IP network. It is like the address of your house, but instead of a house number, street, city, state, zipcode, it looks something like this: 127.0.0.1 Each device on the Internet gets assigned a unique IP Address. No two devices can have the same IP Address just like no two houses on your street have the exact same address.
For what is an IP Address used?
When your computer is on the Internet, anything you do requires data to be transmitted and received. For example, when you visit a web site, such as ForMyIP.com, data is transmitted to your computer in order to load the content of the web page. The server where ForMyIP.com is located needs to know where to send the data. When you connect to ForMyIP.com, it receives your IP Address and then knows where to send the data. For example, someone that needs to mail you a letter has to know your address in order to send it to you just like a server needs to know your IP Address to send you data. To LEARN MORE on IP addresses, some recommended reading is Understanding IP Addressing at Webopedia.
Decoding your IP Address
Your IP Address tells can provide a lot of information such as your approximate location (city, state, country), your Internet Service Provider (e.g. AOL, Earthlink, Mindspring), and even your approximate longitude and latitude. ForMyIP.com lets you LEARN MORE about your IP and location information (city, state, country, ISP).
Who assigns IP Addresses? Just like your home address is decided by your local city or postal service, there are four nonprofit agencies, called Internet registries, that are in charge of assigning IP Addresses: ARIN, RIPE NCC, LACNIC and APNIC. Each Internet registry is responsible for a different region of the world.
What are hosts and how are they related to IP Addresses?
Remembering IP Addresses for sites can be difficult. For example, if you want to go to your friend's house, you know where it is, but you don't tell people you're going to an address, you tell them you're going to your friend's house. The Internet works in much of the same way. Each IP Address has the option of being resolved (converted) into a host. For example, CNN.com resolves to 64.236.16.84. Either visiting the IP Address or the Host will take you to CNN.com's web page. It is much easier to remember CNN.com than to remember the IP Address it resolves to.
How many IP Address combinations can there be? What will be done when they run out?
There can be 4.3 billion combinations of IP Addresses. The current system of IP Addresses is called IPv4. The IPv4 exhaustion of IP Addresses is being resolved with a new system called IPv6.
Where can I find more information?
One of the best resources to search for information about is Google.
Inside this Article 1. Introduction to What is an IP address? 2. Other IP Classes 3. Lots More Information 4. See all Internet Basics articles Every machine on the Internet has a unique identifying number, called an IP Address. A typical IP address looks like this:
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216.27.61.137
To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a "dotted decimal number" like the one above. But computers communicate in binary form. Look at the same IP address in binary:
y
11011000.00011011.00111101.10001001
The four numbers in an IP address are called octets, because they each have eight positions when viewed in binary form. If you add all the positions together, you get 32, which is why IP
addresses are considered 32-bit numbers. Since each of the eight positions can have two different states (1 or 0) the total number of possible combinations per octet is 28 or 256. So each octet can contain any value between 0 and 255. Combine the four octets and you get 232 or a possible 4,294,967,296 unique values! Out of the almost 4.3 billion possible combinations, certain values are restricted from use as typical IP addresses. For example, the IP address 0.0.0.0 is reserved for the default network and the address 255.255.255.255 is used for broadcasts. The octets serve a purpose other than simply separating the numbers. They are used to create classes of IP addresses that can be assigned to a particular business, government or other entity based on size and need. The octets are split into two sections: Net and Host. The Net section always contains the first octet. It is used to identify the network that a computer belongs to. Host (sometimes referred to as Node) identifies the actual computer on the network. The Host section always contains the last octet. There are five IP classes plus certain special addresses:
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Default Network - The IP address of 0.0.0.0 is used for the default network. Class A - This class is for very large networks, such as a major international company might have. IP addresses with a first octet from 1 to 126 are part of this class. The other three octets are used to identify each host. This means that there are 126 Class A networks each with 16,777,214 (224 -2) possible hosts for a total of 2,147,483,648 (231) unique IP addresses. Class A networks account for half of the total available IP addresses. In Class A networks, the high order bit value (the very first binary number) in the first octet is always 0.
Net 115. Host or Node 24.53.107
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Loopback - The IP address 127.0.0.1 is used as the loopback address. This means that it is used by the host computer to send a message back to itself. It is commonly used for troubleshooting and network testing. Class B - Class B is used for medium-sized networks. A good example is a large college campus. IP addresses with a first octet from 128 to 191 are part of this class. Class B addresses also include the second octet as part of the Net identifier. The other two octets are used to identify each host. This means that there are 16,384 (214) Class B networks each with 65,534 (216 -2) possible hosts for a total of 1,073,741,824 (230) unique IP addresses. Class B networks make up a quarter of the total available IP addresses. Class B networks have a first bit value of 1 and a second bit value of 0 in the first octet. Net 145.24. Host or Node 53.107
y
Class C - Class C addresses are commonly used for small to mid-size businesses. IP addresses with a first octet from 192 to 223 are part of this class. Class C addresses also
include the second and third octets as part of the Net identifier. The last octet is used to identify each host. This means that there are 2,097,152 (221) Class C networks each with 254 (28 -2) possible hosts for a total of 536,870,912 (229) unique IP addresses. Class C networks make up an eighth of the total available IP addresses. Class C networks have a first bit value of 1, second bit value of 1 and a third bit value of 0 in the first octet. Net 195.24.53. Host or Node 107
y
Class D - Used for multicasts, Class D is slightly different from the first three classes. It has a first bit value of 1, second bit value of 1, third bit value of 1 and fourth bit value of 0. The other 28 bits are used to identify the group of computers the multicast message is intended for. Class D accounts for 1/16th (268,435,456 or 228) of the available IP addresses. Net 224. Host or Node 24.53.107
y
Class E - Class E is used for experimental purposes only. Like Class D, it is different from the first three classes. It has a first bit value of 1, second bit value of 1, third bit value of 1 and fourth bit value of 1. The other 28 bits are used to identify the group of computers the multicast message is intended for. Class E accounts for 1/16th (268,435,456 or 228) of the available IP addresses. Net 240. Host or Node 24.53.107
y
Broadcast - Messages that are intended for all computers on a network are sent as broadcasts. These messages always use the IP address 255.255.255.255.
An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.[1] An IP address serves two principal functions: host or network interface identification and location addressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."[2] The designers of the Internet Protocol defined an IP address as a 32-bit number[1] and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of the Internet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995,[3] standardized as RFC 2460 in 1998,[4] and is being deployed worldwide since the mid-2000s. IP addresses are binary numbers, but they are usually stored in text files and displayed in humanreadable notations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6). The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally and delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries (Internet service providers) and other entities. Dynamic IP addresses are temporary and are assigned each time a computer accesses the Internet. They are, in effect, borrowed from a pool of IP addresses that are shared among various computers. Since a limited number of static IP addresses are available, many ISPs reserve a portion of their assigned addresses for sharing among their subscribers in this way. This lowers costs and allows them to service far more subscribers than they otherwise could. Static IP addresses are generally preferable for such uses as VOIP (Voice over Internet Protocol), online gaming, or any other purpose where users need to make it easy for other computers to locate and connect to them. Easy access can also be facilitated when using a dynamic IP address through the use of a dynamic DNS service, which enables other computers to find you even though you may be using a temporary, one-time IP address. This often entails an extra charge, however, so check with your ISP. Static IP addresses are considered somewhat less secure than dynamic IP addresses, since they are easier to track for data mining purposes. However, following safe Internet practices can help mitigate this potential problem and keep your computer secure no matter what type of IP address you use. What is an IP Address? "An identifier for a computer or device on a TCP/IP network" as defined by Webopedia. In simple terms, its a number that consists of four numbers, separated by periods, that can be between 0 and 255. This number identifies the device (e.g. comptuer) that is connected to the
Internet, which is a TCP/IP network. It is like the address of your house, but instead of a house number, street, city, state, zipcode, it looks something like this: 127.0.0.1 Each device on the Internet gets assigned a unique IP Address. No two devices can have the same IP Address just like no two houses on your street have the exact same address.
For what is an IP Address used?
When your computer is on the Internet, anything you do requires data to be transmitted and received. For example, when you visit a web site, such as ForMyIP.com, data is transmitted to your computer in order to load the content of the web page. The server where ForMyIP.com is located needs to know where to send the data. When you connect to ForMyIP.com, it receives your IP Address and then knows where to send the data. For example, someone that needs to mail you a letter has to know your address in order to send it to you just like a server needs to know your IP Address to send you data. To LEARN MORE on IP addresses, some recommended reading is Understanding IP Addressing at Webopedia.
Decoding your IP Address
Your IP Address tells can provide a lot of information such as your approximate location (city, state, country), your Internet Service Provider (e.g. AOL, Earthlink, Mindspring), and even your approximate longitude and latitude. ForMyIP.com lets you LEARN MORE about your IP and location information (city, state, country, ISP).
Who assigns IP Addresses? Just like your home address is decided by your local city or postal service, there are four nonprofit agencies, called Internet registries, that are in charge of assigning IP Addresses: ARIN, RIPE NCC, LACNIC and APNIC. Each Internet registry is responsible for a different region of the world.
What are hosts and how are they related to IP Addresses?
Remembering IP Addresses for sites can be difficult. For example, if you want to go to your friend's house, you know where it is, but you don't tell people you're going to an address, you tell them you're going to your friend's house. The Internet works in much of the same way. Each IP Address has the option of being resolved (converted) into a host. For example, CNN.com resolves to 64.236.16.84. Either visiting the IP Address or the Host will take you to CNN.com's web page. It is much easier to remember CNN.com than to remember the IP Address it resolves to.
How many IP Address combinations can there be? What will be done when they run out?
There can be 4.3 billion combinations of IP Addresses. The current system of IP Addresses is called IPv4. The IPv4 exhaustion of IP Addresses is being resolved with a new system called IPv6.
Where can I find more information?
One of the best resources to search for information about is Google.
Inside this Article 1. Introduction to What is an IP address? 2. Other IP Classes 3. Lots More Information 4. See all Internet Basics articles Every machine on the Internet has a unique identifying number, called an IP Address. A typical IP address looks like this:
y
216.27.61.137
To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a "dotted decimal number" like the one above. But computers communicate in binary form. Look at the same IP address in binary:
y
11011000.00011011.00111101.10001001
The four numbers in an IP address are called octets, because they each have eight positions when viewed in binary form. If you add all the positions together, you get 32, which is why IP
addresses are considered 32-bit numbers. Since each of the eight positions can have two different states (1 or 0) the total number of possible combinations per octet is 28 or 256. So each octet can contain any value between 0 and 255. Combine the four octets and you get 232 or a possible 4,294,967,296 unique values! Out of the almost 4.3 billion possible combinations, certain values are restricted from use as typical IP addresses. For example, the IP address 0.0.0.0 is reserved for the default network and the address 255.255.255.255 is used for broadcasts. The octets serve a purpose other than simply separating the numbers. They are used to create classes of IP addresses that can be assigned to a particular business, government or other entity based on size and need. The octets are split into two sections: Net and Host. The Net section always contains the first octet. It is used to identify the network that a computer belongs to. Host (sometimes referred to as Node) identifies the actual computer on the network. The Host section always contains the last octet. There are five IP classes plus certain special addresses:
y y
Default Network - The IP address of 0.0.0.0 is used for the default network. Class A - This class is for very large networks, such as a major international company might have. IP addresses with a first octet from 1 to 126 are part of this class. The other three octets are used to identify each host. This means that there are 126 Class A networks each with 16,777,214 (224 -2) possible hosts for a total of 2,147,483,648 (231) unique IP addresses. Class A networks account for half of the total available IP addresses. In Class A networks, the high order bit value (the very first binary number) in the first octet is always 0.
Net 115. Host or Node 24.53.107
y
y
Loopback - The IP address 127.0.0.1 is used as the loopback address. This means that it is used by the host computer to send a message back to itself. It is commonly used for troubleshooting and network testing. Class B - Class B is used for medium-sized networks. A good example is a large college campus. IP addresses with a first octet from 128 to 191 are part of this class. Class B addresses also include the second octet as part of the Net identifier. The other two octets are used to identify each host. This means that there are 16,384 (214) Class B networks each with 65,534 (216 -2) possible hosts for a total of 1,073,741,824 (230) unique IP addresses. Class B networks make up a quarter of the total available IP addresses. Class B networks have a first bit value of 1 and a second bit value of 0 in the first octet. Net 145.24. Host or Node 53.107
y
Class C - Class C addresses are commonly used for small to mid-size businesses. IP addresses with a first octet from 192 to 223 are part of this class. Class C addresses also
include the second and third octets as part of the Net identifier. The last octet is used to identify each host. This means that there are 2,097,152 (221) Class C networks each with 254 (28 -2) possible hosts for a total of 536,870,912 (229) unique IP addresses. Class C networks make up an eighth of the total available IP addresses. Class C networks have a first bit value of 1, second bit value of 1 and a third bit value of 0 in the first octet. Net 195.24.53. Host or Node 107
y
Class D - Used for multicasts, Class D is slightly different from the first three classes. It has a first bit value of 1, second bit value of 1, third bit value of 1 and fourth bit value of 0. The other 28 bits are used to identify the group of computers the multicast message is intended for. Class D accounts for 1/16th (268,435,456 or 228) of the available IP addresses. Net 224. Host or Node 24.53.107
y
Class E - Class E is used for experimental purposes only. Like Class D, it is different from the first three classes. It has a first bit value of 1, second bit value of 1, third bit value of 1 and fourth bit value of 1. The other 28 bits are used to identify the group of computers the multicast message is intended for. Class E accounts for 1/16th (268,435,456 or 228) of the available IP addresses. Net 240. Host or Node 24.53.107
y
Broadcast - Messages that are intended for all computers on a network are sent as broadcasts. These messages always use the IP address 255.255.255.255.
