27.131.130.0/24

inetnum:        27.131.130.0 - 27.131.130.255
netname:        Leaseline_Customer
descr:          KIRZ Leaseline Network
country:        TH
admin-c:        GK263-AP
tech-c:         GK263-AP
status:         ALLOCATED NON-PORTABLE
mnt-by:         MAINT-TH-KIRZ
mnt-lower:      MAINT-TH-KIRZ
mnt-routes:     MAINT-TH-KIRZ
mnt-irt:        IRT-KIRZ-TH
changed:        sarayut@kirz.com 20130530
source:         APNIC

irt:            IRT-KIRZ-TH
address:        192 Soi Ladprao 107
address:        Bangkapi, Bangkok 10240
address:        Thailand
e-mail:         sak@kirz.com
abuse-mailbox:  sak@kirz.com
admin-c:        GK263-AP
tech-c:         GK263-AP
auth:           # Filtered
mnt-by:         MAINT-TH-KIRZ
changed:        sak@kirz.com 20101125
source:         APNIC

person:         Gun Kirdkao
nic-hdl:        GK263-AP
e-mail:         gun@kirz.com
address:        192 Soi Ladprao 107
address:        Bangkapi
phone:          +66-0-1834-0888
fax-no:         +66-0-2731-1140
country:        TH
changed:        gun@kirz.com 20051012
mnt-by:         MAINT-NEW
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.