2600:6:ff42::/48 - SPRINT-PHOENIX-POP
V6NetHandle: NET6-2600-6-FF42-4000-1 OrgID: SPP-90 Parent: NET6-2600-2 NetName: SPRINT-PHOENIX-POP NetRange: 2600:6:FF42:4000:: - 2600:6:FF42:4FFF:FFFF:FFFF:FFFF:FFFF NetType: reassignment RegDate: 2017-10-19 Updated: 2017-10-19 Source: ARIN OrgID: SPP-90 OrgName: Sprint Phoenix POP CanAllocate: Street: Sprint Phoenix POP City: Phoenix State/Prov: AZ Country: US PostalCode: 85040 RegDate: 2013-12-06 Updated: 2013-12-06 OrgTechHandle: SIE-ARIN OrgAdminHandle: SIE-ARIN OrgAbuseHandle: SIE-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.