2001:738:4::/48 - ISZT-NET
inet6num: 2001,738,4,,/48 netname: ISZT-NET descr: Internet Szolgaltatok Tanacsa (ISZT) descr: Council of Hungarian Internet Providers (CHIP) country: HU admin-c: BM209-RIPE tech-c: ZK106-RIPE remarks: rev-srv, 184.108.40.206 status: ASSIGNED mnt-by: NIIF6-MNT mnt-routes: HU-NIC-MNT created: 2006-11-23T17,30,30Z last-modified: 2009-09-02T19,33,48Z source: RIPE remarks: rev-srv attribute deprecated by RIPE NCC on 02/09/2009 person: Balazs Martos address: Council of Hungarian Internet Providers address: Internet Szolgaltatok Tanacsa address: Victor Hugo u. 18-22. address: H-1132 Budapest address: Hungary phone: +36 1 2380115 fax-no: +36 1 2380114 e-mail: email@example.com nic-hdl: BM209-RIPE mnt-by: HU-NIC-MNT created: 2002-02-26T16,47,42Z last-modified: 2002-02-26T16,47,42Z source: RIPE person: Zoltan Kalmar address: Council of Hungarian Internet Providers address: Internet Szolgaltatok Tanacsa address: Victor Hugo u. 18-22. address: H-1132 Budapest address: Hungary phone: +36 1 2380115 fax-no: +36 1 2380114 e-mail: firstname.lastname@example.org nic-hdl: ZK106-RIPE mnt-by: HU-NIC-MNT created: 1970-01-01T00,00,00Z last-modified: 2014-03-14T12,29,56Z source: RIPE route6: 2001,738,4,,/48 descr: Council of Hungarian Internet Providers origin: AS12303 mnt-by: HU-NIC-MNT created: 2008-05-29T08,42,07Z last-modified: 2008-05-29T08,42,07Z source: RIPE
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.