2001:500:3682::/48 - ULTRADNS
V6NetHandle: NET6-2001-500-3682-1 OrgID: NEUS Parent: NET6-2001-400-0 NetName: ULTRADNS NetRange: 2001:500:3682:: - 2001:500:3682:FFFF:FFFF:FFFF:FFFF:FFFF NetType: allocation RegDate: 2010-10-08 Updated: 2012-03-02 TechHandle: NETWO336-ARIN Source: ARIN OrgID: NEUS OrgName: NeuStar, Inc. CanAllocate: Street: 45980 Center Oak Plaza Street: Network Operations Center City: Sterling State/Prov: VA Country: US PostalCode: 20166 Comment: NPAC RegDate: 2001-03-21 Updated: 2018-01-10 OrgAbuseHandle: NETWO336-ARIN OrgAdminHandle: NETWO336-ARIN OrgTechHandle: NETWO336-ARIN Source: ARIN
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.