Classless Inter-Domain Routing - Wikipedia, the free encyclopedia
IPv4 CIDR IP/CIDR Δ to last IP addr Mask Count of addresses Relative size to other block sizes Restrictions on a/b/c/d (0..255 unless noted) a.b.c.d/32 +0.0.0.0 255.255.255.255 1 1/256 C a.b.c.d/31 +0.0.0.1 255.255.255.254 2 1/128 C d = 0 ... (2n) ... 254...