Look at the first group of digits on the left. It determines the class of an IPaddress. There are only five. They are designated by the first five letters of the Latin alphabet: A, B, C, D, E. They are distinguished by a numeric value. Class A is from 1 to 126, from 128 to 191, C - 192 to 223, D - 224 to 239 and E - 240 to 247. The classes differ in the number of bits of network numbers and host, and this affects the breadth of interval values. Classes A, b and C are used to send information to individual nodes or network linked computers. But such broadcasts are not always needed. When you need to select a group of nodes that are not members of a common network, using a class D. While the range of E is still in reserve.
Eliminate the possibility that a special IP ' mi. These include, for example, those whose first three digits are 127. In this case, the computer receives data from itself, and the data is processed on the source host. Typically, this address is written to test. The opposite is the IP 255.255.255.255, which sends data to all nodes on the network and is used for limited broadcast. In addition, the service address is 0.0.0.0., which serves for identity of the node sender.
Find out whether the IP address was local. These include those first two groups of figures which is 192.168. Use them to configure local networks.
Check the IP address on any of the specialized Internet services. Entering the address or domain, you will get maximum of information, to whom and where he belongs. Do it, for example, on the websites 1whois.ru, whois-service.ru or 2ip.ru/whois/.
Translate IP to domain using special scripts. This check propose to do here - http://www.ifstudio.org/seo/ipreverse.php. If the IP does not correspond to any domain, the service will not give out any information.
Use the utility "Network calculator" or similar for calculation of IP addresses that are required when configuring network services. Such a lot of offers on different sites - for example, you can use ip-ping.ru, allcalc.ru or ispreview.ru.