Skip to main content

What is an IP address?

Every machine on the Internet­ has a unique identifying number, called an IP Address. A typical IP address looks like this:
  • 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:
  • 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 broadcast.

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:
  • 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
Host or Node
115.
24.53.107
  • 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.
Labels:

Comments

Post a Comment

Popular posts from this blog

Background Process in ORACLE Database

Background Process in ORACLE Database Database Writer Process (DBWn) Log Writer Process (LGWR) Checkpoint Process (CKPT) System Monitor Process (SMON) Process Monitor Process (PMON) Recoverer Process (RECO) Job Queue Processes Archiver Processes (ARCn) Queue Monitor Processes (QMNn) Database Writer Process (DBWn) The database writer process (DBWn) writes the contents of buffers to datafiles. The DBWn processes are responsible for writing modified (dirty) buffers in the database buffer cache to disk. Although one database writer process (DBW0) is adequate for most systems, you can configure additional processes (DBW1 through DBW9 and DBWa through DBWj) to improve write performance if your system modifies data heavily. These additional DBWn processes are not useful on uniprocessor systems. When a buffer in the database buffer cache is modified, it is marked dirty. A cold buffer is a buffer that has not been recently used according to the least recently used (LRU) algorith...
Post a Comment
Read more

Using GREP in UNIX

How To Use grep Command In Linux / UNIX by  VIVEK GITE  on  AUGUST 2, 2007  ·  147 COMMENTS H ow do I use grep command in Linux? grep command searches the given file for lines containing a match to the given strings or words. By default, grep prints the matching lines. Use grep to search for lines of text that match one or many regular expressions, and outputs only the matching lines. The name, "grep", derives from the command used to perform a similar operation, using the Unix/Linux text editor ed: g/re/p grep command syntax grep 'word' filename grep 'string1 string2' filename cat otherfile | grep 'something' command | grep 'something' Use grep to search file Search /etc/passwd for boo user: $ grep boo /etc/passwd You can force grep to ignore word case i.e match boo, Boo, BOO and all other combination with -i option: $ grep -i "boo" /etc/passwd Use grep recursively You can search recursively i.e. read all files under each ...
Post a Comment
Read more

SBI IBPS IT Officer Scoring Topics #1

G3 is a computer CHIP If instruction RST-5 is written in a program, the program control will jump to location 0028H . TOP-DOWN is a tree PREORDER traversing . An Operand STACK is essential for conversion to INFIX Expression. Header of IP is FIXED part of 20 Bytes. FENCE register is used for MEMORY PROTECTION . YACC semantic action is sequence of C Statements. s Symbol represents SYMMETRIC DIFFERENCE. E.g. AsB 5 th NF is related to JOIN DEPENDENCY. 8086 Microprocessor is a 16 bit Processor. A total of about 1 million bytes can be directly addressed by the 8086 microprocessor 8086 has 8 flags Compare to 8086, the 80286 provides a higher degree of memory operation The address space of 8086 Microprocessor is 2 16 = 1MB. The action of parsing the source program into the proper syntactic classes is known as LEXICAL ANALYSIS. Printf() in C used to print “character, string, float, integer, octal and hexadecimal values” onto the output scree...
Post a Comment
Read more