37.139.0.0/19

inetnum:        37.139.0.0 - 37.139.31.255
netname:        US-DIGITALOCEANLLC-20120224
country:        NL
abuse-c:        AD10778-RIPE
org:            ORG-DOI2-RIPE
admin-c:        PT7353-RIPE
tech-c:         PT7353-RIPE
status:         ALLOCATED PA
mnt-by:         RIPE-NCC-HM-MNT
mnt-by:         digitalocean
mnt-routes:     digitalocean
notify:         abuse@digitalocean.com
mnt-domains:    digitalocean
created:        2013-06-14T11:56:59Z
last-modified:  2019-04-15T19:26:57Z
source:         RIPE

organisation:   ORG-DOI2-RIPE
org-name:       DigitalOcean, LLC
org-type:       LIR
address:        101 Avenue of the Americas, 10th Floor
address:        New York
address:        10013
address:        UNITED STATES
phone:          +1 888 890 6714
mnt-ref:        digitalocean
mnt-ref:        RIPE-NCC-HM-MNT
mnt-by:         RIPE-NCC-HM-MNT
mnt-by:         digitalocean
abuse-c:        AD10778-RIPE
e-mail:         noc@digitalocean.com
notify:         noc@digitalocean.com
language:       EN
created:        2012-11-29T14:59:01Z
last-modified:  2019-04-17T14:37:00Z
source:         RIPE

person:         Network Operations
address:        101 Ave of the Americas, 10th Floor
address:        New York, NY, 10013
address:        United States of America
phone:          +13478756044
nic-hdl:        PT7353-RIPE
mnt-by:         digitalocean
created:        2015-03-11T16:37:07Z
last-modified:  2019-04-17T14:37:51Z
source:         RIPE
e-mail:         noc@digitalocean.com
org:            ORG-DOI2-RIPE
notify:         noc@digitalocean.com

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.