Help:Range blocks

Range blocks are technical restrictions applied through Special:Blockip to a group of IP addresses that prevent them from editing, creating new accounts, sending email through the wiki interface, et cetera. Registered accounts editing from these IP addresses will also be blocked, unless you check the box to only block anonymous editors.

Range blocking is enabled on all Wikimedia wikis; to enable it on other wikis, add " " in LocalSettings.php.

How to block ranges
To block an IP range from Special:Blockip, enter the first IP address in the range followed by a forward slash and a Classless inter-domain routing (CIDR) suffix.

Technical explanation
CIDR notation involves converting the IP address to a 32-bit binary representation and suffixing the number of prefixing bits all IP addresses to be blocked have in common.

For example: " " is binary " ", so  will match the first 27 digits (" "). The IP addresses –, when converted to binary, all have the same 27 first digits and will be blocked by.

Table
The table below shows the IP blocks each CIDR suffix affects. Note that MediaWiki only supports blocking CIDR suffixes 16–32.