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. You should avoid performing range blocks unless you understand what you are doing, or you may end up blocked tens of thousands of people who are not the problem!

Technical explanation
CIDR notation is written as the IP address, a slash, and the CIDR affix (for example, the IPv4 " " or IPv6 " "). The CIDR affix is the number of starting digits every IP address in the range have in common when written in binary.

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 if   is blocked.

As the CIDR affix increases, the block affects less IP addresses (see table of example ranges). CIDR affixes are not the same for IPv4 addresses as they are for IPv6 addresses.

Calculating the CIDR affix
You can use the table of sample ranges below to guess the range, or manually calculate the range:
 * 1) Convert the first and last IP addresses in the range to binary using the list below.
 * 2) Place both IP addresses one atop the other, and count how many starting digits are exactly alike. This is the CIDR affix.
 * 3) Double-check! Being off by one digit could extend your block by thousands of addresses.

The example below calculates the CIDR range between 69.208.0.0 and 69.208.0.255. Note that this is a simple example; some groups of IP addresses do not so neatly fit CIDR affixes, and need multiple different-sized blocks to block the exact range. IP addresses: 69.208.0.0  69.208.0.255 Convert to binary: 0100 0101.1101 0000.0000 0000.0000 0000  0100 0101.1101 0000.0000 0000.1111 1111 Count identical first numbers: 0100 0101.1101 0000.0000 0000.0000 0000  0100 0101.1101 0000.0000 0000.1111 1111   |____________________________|             24 digits CIDR range: 69.208.0.0/24

List of decimal->binary conversions
 Decimal -> Binary 0 -> 0000 0000 1 -> 0000 0001 2 -> 0000 0010 3 -> 0000 0011 4 -> 0000 0100 5 -> 0000 0101 6 -> 0000 0110 7 -> 0000 0111 8 -> 0000 1000 9 -> 0000 1001 10 -> 0000 1010 11 -> 0000 1011 12 -> 0000 1100 13 -> 0000 1101 14 -> 0000 1110 15 -> 0000 1111 16 -> 0001 0000 17 -> 0001 0001 18 -> 0001 0010 19 -> 0001 0011 20 -> 0001 0100 21 -> 0001 0101 22 -> 0001 0110 23 -> 0001 0111 24 -> 0001 1000 25 -> 0001 1001 		 	 26 -> 0001 1010 	 	 	 27 -> 0001 1011 	 	 	 28 -> 0001 1100 	 	 	 29 -> 0001 1101 	 	 	 30 -> 0001 1110 	 	 	 31 -> 0001 1111 	 	 	 32 -> 0010 0000 	 	 	 33 -> 0010 0001 	 	 	 34 -> 0010 0010 	 	 	 35 -> 0010 0011 	 	 	 36 -> 0010 0100 	 	 	 37 -> 0010 0101 	 	 	 38 -> 0010 0110 	 	 	 39 -> 0010 0111 	 	 	 40 -> 0010 1000 	 	 	 41 -> 0010 1001 	 	 	 42 -> 0010 1010 	 	 	 43 -> 0010 1011 	 	 	 44 -> 0010 1100 	 	 	 45 -> 0010 1101 	 	 	 46 -> 0010 1110 	 	 	 47 -> 0010 1111 	 	 	 48 -> 0011 0000 	 	 	 49 -> 0011 0001 	 	 	 50 -> 0011 0010 	 	 	 51 -> 0011 0011 	 	 	 52 -> 0011 0100 	 	 	 53 -> 0011 0101 	 	 	 54 -> 0011 0110 	 	 	 55 -> 0011 0111 	 	 	 56 -> 0011 1000 	 	 	 57 -> 0011 1001 	 	 	 58 -> 0011 1010 	 	 	 59 -> 0011 1011 	 	 	 60 -> 0011 1100 	 	 	 61 -> 0011 1101 	 	 	 62 -> 0011 1110 	 	 	 63 -> 0011 1111 	 	 	 64 -> 0100 0000 65 -> 0100 0001 66 -> 0100 0010 67 -> 0100 0011 68 -> 0100 0100 69 -> 0100 0101 70 -> 0100 0110 71 -> 0100 0111 72 -> 0100 1000 73 -> 0100 1001 74 -> 0100 1010 75 -> 0100 1011 76 -> 0100 1100 77 -> 0100 1101 78 -> 0100 1110 79 -> 0100 1111 80 -> 0101 0000 81 -> 0101 0001 82 -> 0101 0010 83 -> 0101 0011 84 -> 0101 0100 85 -> 0101 0101 86 -> 0101 0110 87 -> 0101 0111 88 -> 0101 1000 89 -> 0101 1001 90 -> 0101 1010 91 -> 0101 1011 92 -> 0101 1100 93 -> 0101 1101 94 -> 0101 1110 95 -> 0101 1111 96 -> 0110 0000 97 -> 0110 0001 98 -> 0110 0010 99 -> 0110 0011 100 -> 0110 0100 101 -> 0110 0101 102 -> 0110 0110 103 -> 0110 0111 104 -> 0110 1000 105 -> 0110 1001 106 -> 0110 1010 107 -> 0110 1011 108 -> 0110 1100 109 -> 0010 1101 110 -> 0110 1110 111 -> 0110 1111 112 -> 0111 0000 113 -> 0111 0001 114 -> 0111 0010 115 -> 0111 0011 116 -> 0111 0100 117 -> 0111 0101 118 -> 0111 0110 119 -> 0111 0111 120 -> 0111 1000 121 -> 0111 1001 122 -> 0111 1010 123 -> 0111 1011 124 -> 0111 1100 125 -> 0111 1101 126 -> 0111 1110 127 -> 0111 1111 128 -> 1000 0000 129 -> 1000 0001 130 -> 1000 0010 131 -> 1000 0011 132 -> 1000 0100 133 -> 1000 0101 134 -> 1000 0110 135 -> 1000 0111 136 -> 1000 1000 137 -> 1000 1001 138 -> 1000 1010 139 -> 1000 1011 140 -> 1000 1100 141 -> 1000 1101 142 -> 1000 1110 143 -> 1000 1111 144 -> 1001 0000 145 -> 1001 0001 146 -> 1001 0010 147 -> 1001 0011 148 -> 1001 0100 149 -> 1001 0101 150 -> 1001 0110 151 -> 1001 0111 152 -> 1001 1000 153 -> 1001 1001 154 -> 1001 1010 155 -> 1001 1011 156 -> 1001 1100 157 -> 1001 1101 158 -> 1001 1110 159 -> 1001 1111 160 -> 1010 0000 161 -> 1010 0001 162 -> 1010 0010 163 -> 1010 0011 164 -> 1010 0100 165 -> 1010 0101 166 -> 1010 0110 167 -> 1010 0111 168 -> 1010 1000 169 -> 1010 1001 170 -> 1010 1010 171 -> 1010 1011 172 -> 1010 1100 173 -> 1010 1101 174 -> 1010 1110 175 -> 1010 1111 176 -> 1011 0000 177 -> 1011 0001 178 -> 1011 0010 179 -> 1011 0011 180 -> 1011 0100 181 -> 1011 0101 182 -> 1011 0110 183 -> 1011 0111 184 -> 1011 1000 185 -> 1011 1001 186 -> 1011 1010 187 -> 1011 1011 188 -> 1011 1100 189 -> 1011 1101 190 -> 1011 1110 191 -> 1011 1111 192 -> 1100 0000 193 -> 1100 0001 194 -> 1100 0010 195 -> 1100 0011 196 -> 1100 0100 197 -> 1100 0101 198 -> 1100 0110 199 -> 1100 0111 200 -> 1100 1000 201 -> 1100 1001 202 -> 1100 1010 203 -> 1100 1011 204 -> 1100 1100 205 -> 1100 1101 206 -> 1100 1110 207 -> 1100 1111 208 -> 1101 0000 209 -> 1101 0001 210 -> 1101 0010 211 -> 1101 0011 212 -> 1101 0100 213 -> 1101 0101 214 -> 1101 0110 215 -> 1101 0111 216 -> 1101 1000 217 -> 1101 1001 218 -> 1101 1010 219 -> 1101 1011 220 -> 1101 1100 221 -> 1101 1101 222 -> 1101 1110 223 -> 1101 1111 224 -> 1110 0000 225 -> 1110 0001 226 -> 1110 0010 227 -> 1110 0011 228 -> 1110 0100 229 -> 1110 0101 230 -> 1110 0110 231 -> 1110 0111 232 -> 1110 1000 233 -> 1110 1001 234 -> 1110 1010 235 -> 1110 1011 236 -> 1110 1100 237 -> 1010 1101 238 -> 1110 1110 239 -> 1110 1111 240 -> 1111 0000 241 -> 1111 0001 242 -> 1111 0010 243 -> 1111 0011 244 -> 1111 0100 245 -> 1111 0101 246 -> 1111 0110 247 -> 1111 0111 248 -> 1111 1000 249 -> 1111 1001 250 -> 1111 1010 251 -> 1111 1011 252 -> 1111 1100 253 -> 1111 1101 254 -> 1111 1110 255 -> 1111 1111

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