Netmask Table Prefix Dotted Decimal Hexadecimal Binary Netmask Length Netmask Netmask ---------------------------------------------------------------------------- /0 0.0.0.0 0x00000000 00000000 00000000 00000000 00000000 /1 128.0.0.0 0x80000000 10000000 00000000 00000000 00000000 /2 192.0.0.0 0xc0000000 11000000 00000000 00000000 00000000 /3 224.0.0.0 0xe0000000 11100000 00000000 00000000 00000000 /4 240.0.0.0 0xf0000000 11110000 00000000 00000000 00000000 /5 248.0.0.0 0xf8000000 11111000 00000000 00000000 00000000 /6 252.0.0.0 0xfc000000 11111100 00000000 00000000 00000000 /7 254.0.0.0 0xfe000000 11111110 00000000 00000000 00000000 /8 255.0.0.0 0xff000000 11111111 00000000 00000000 00000000 /9 255.128.0.0 0xff800000 11111111 10000000 00000000 00000000 /10 255.192.0.0 0xffc00000 11111111 11000000 00000000 00000000 /11 255.224.0.0 0xffe00000 11111111 11100000 00000000 00000000 /12 255.240.0.0 0xfff00000 11111111 11110000 00000000 00000000 /13 255.248.0.0 0xfff80000 11111111 11111000 00000000 00000000 /14 255.252.0.0 0xfffc0000 11111111 11111100 00000000 00000000 /15 255.254.0.0 0xfffe0000 11111111 11111110 00000000 00000000 /16 255.255.0.0 0xffff0000 11111111 11111111 00000000 00000000 /17 255.255.128.0 0xffff8000 11111111 11111111 10000000 00000000 /18 255.255.192.0 0xffffc000 11111111 11111111 11000000 00000000 /19 255.255.224.0 0xffffe000 11111111 11111111 11100000 00000000 /20 255.255.240.0 0xfffff000 11111111 11111111 11110000 00000000 /21 255.255.248.0 0xfffff800 11111111 11111111 11111000 00000000 /22 255.255.252.0 0xfffffc00 11111111 11111111 11111100 00000000 /23 255.255.254.0 0xfffffe00 11111111 11111111 11111110 00000000 /24 255.255.255.0 0xffffff00 11111111 11111111 11111111 00000000 /25 255.255.255.128 0xffffff80 11111111 11111111 11111111 10000000 /26 255.255.255.192 0xffffffc0 11111111 11111111 11111111 11000000 /27 255.255.255.224 0xffffffe0 11111111 11111111 11111111 11100000 /28 255.255.255.240 0xfffffff0 11111111 11111111 11111111 11110000 /29 255.255.255.248 0xfffffff8 11111111 11111111 11111111 11111000 /30 255.255.255.252 0xfffffffc 11111111 11111111 11111111 11111100 /31 255.255.255.254 0xfffffffe 11111111 11111111 11111111 11111110 /32 255.255.255.255 0xffffffff 11111111 11111111 11111111 11111111 Source: http://www.bgp4.as/