2404:0:6000::/36

inet6num:       2404::/26
netname:        ETWEBS-TWNIC-TW-20060125
descr:          Asia Pacific Online Service Inc.
descr:          3F., Building C,No.19-6,Sanchong Road,Nan Kang Dist.
descr:          Taipei 115,Taiwan
country:        TW
admin-c:        HE6-AP
tech-c:         HE6-AP
mnt-by:         MAINT-TW-TWNIC
mnt-lower:      MAINT-TW-TWNIC
status:         ALLOCATED PORTABLE
last-modified:  2008-09-04T06:49:19Z
source:         APNIC


person:         Hostmaster ETWebs
nic-hdl:        HE6-AP
e-mail:         admin@ethome.net
address:        8F, No.19-5, San-Chong Rd., Nan-Guang Dist.,
address:        Taipei City, Taiwan, R.O.C.
phone:          +886-2-55813300
fax-no:         +886-2-26551515
country:        TW
mnt-by:         MAINT-TW-TWNIC
last-modified:  2008-09-04T07:29:18Z
source:         APNIC

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.