User:Millosh/IP range block

You should read fistly Help:Block_and_unblock!

1. IP address is consited of four numbers separated by dots, let's name them with A.B.C.D.
2. If you don't see that any of those numbers are varying, block the exact number.
   • Possible problem: Some large groups of internet users are using only one proxy server. This would imply that you would block a lot of other users.
3. If you see that only number D is varying -- you should block C class of IP addresses: A.B.C.0/24 (for example: 192.168.1.0/24).
   • Possible problem: Some small countries and some bigger countries, but without good Internet infrastructure, may lay only on one C class. This would imply that you would block the whole country.
4. If you see that even C number is varying, you may use one of the two methods: (1) block relevant C classes (for example: 192.168.1.0/24, 192.168.15.0/24 etc.) or (2) block the whole B class: A.B.0.0/16 (for example: 192.168.0.0/16).
   • Possible problem: By blocking B class, you would block a very wide range of users, like all users which use Telecom Italia as their provider.
5. If you see that even B number is varying, don't block A class! There is a very small number of companies which have A class and your block may affect maybe 100 millions of possible users.
6. In all cases:
   • If you are not well introduced in the Internet technology, tell to other admins (especially those who are introduced in Internet technology) what did you do.
   • You may use service like RIPE whois database is.
     • RIPE is delegated to work only with European companies, and because of that you may not be able to find informations for the relevant number.
     • For whois services of other Regional Internet registries, see the page on English Wikipedia.
     • Usually, you will even get the relevant number which should be blocked, like "82.56.0.0/16" is, under the field "route". Use the biggest possible number at the end (/16), which means the smallest possible IP range!
     • For example, my ADSL (dynamic) IP address yesterday was 81.18.52.54. By querying RIPE, you will get a lot of informations, but inside of them two most important: 81.18.48.0/20 for "NeoBee.net LIR Allocation Route" and 81.18.48.0/21 for "NeoBee.net ADSL Pool Route". As my address was inside of both of them, and the smaller IP range (the bigger number) is 82.18.48.0/21, you should block that one. At least, you may see that this one is less general then the bigger one by name. Usually, you will get such informations from RIPE or any other Regional Internet registry.