2001:12d8::/32 - LFL4
inetnum: 2001:12d8::/32 aut-num: AS1251 abuse-c: JMA135 owner: FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO SÃO PAULO ownerid: 43.828.151/0001-45 responsible: Luis Fernandez Lopez owner-c: LFL180 tech-c: JMA135 inetrev: 2001:12d8:80::/48 nserver: ns.sprace.org.br nsstat: 20170305 AA nslastaa: 20170305 nserver: ns1.ansp.br nsstat: 20170305 AA nslastaa: 20170305 inetrev: 2001:12d8:81::/48 nserver: ns1.ansp.br nsstat: 20170306 AA nslastaa: 20170306 nserver: ns2.ansp.br nsstat: 20170306 AA nslastaa: 20170306 inetrev: 2001:12d8:88::/48 nserver: ns1.ansp.br nsstat: 20170305 AA nslastaa: 20170305 nserver: ns2.ansp.br nsstat: 20170305 AA nslastaa: 20170305 created: 20071219 changed: 20130308 nic-hdl-br: LFL180 person: Luis Fernandez Lopez created: 20030427 changed: 20120930 nic-hdl-br: JMA135 person: Jorge Marcos de Almeida created: 20020226 changed: 20150921
IP address ranges, or netblocks, are groups of related IP addresses. They are usually represented as a base IP address, followed by a slash, and then a netmask which represents how many IP addresses are contained within the netblock. This format is known as CIDR. You'll also sometimes see netblocks given as a start ip address, and an end ip address, or an ip address range.
Traffic works its way around the internet based on the routing table, which contains a list of networks and their associated netblocks.