200.61.21.0/24

inetnum:     200.61.16/21
status:      reallocated
owner:       Silica Networks Argentina S.A.
ownerid:     AR-SISA3-LACNIC
responsible: Ignacio Lopez
address:     San Martin, -, 638
address:     C1004AAN - Buenos Aires - BA
country:     AR
phone:       +54 11 43233300 []
owner-c:     SNC2
tech-c:      SNC2
abuse-c:     SNC2
inetrev:     200.61.16/23
nserver:     NS1.SILICANETWORKS.NET.AR  
nsstat:      20170303 AA
nslastaa:    20170303
nserver:     NS2.SILICANETWORKS.NET.AR  
nsstat:      20170303 AA
nslastaa:    20170303
inetrev:     200.61.19/24
nserver:     NS1.SILICANETWORKS.NET.AR  
nsstat:      20170304 AA
nslastaa:    20170304
nserver:     NS2.SILICANETWORKS.NET.AR  
nsstat:      20170304 AA
nslastaa:    20170304
inetrev:     200.61.20/22
nserver:     NS1.SILICANETWORKS.NET.AR  
nsstat:      20170303 AA
nslastaa:    20170303
nserver:     NS2.SILICANETWORKS.NET.AR  
nsstat:      20170303 AA
nslastaa:    20170303
created:     20080417
changed:     20080417
inetnum-up:  200.61.16/20

nic-hdl:     SNC2
person:      Javier Ignacio Rodriguez Sotelo
e-mail:      abuse-silica@DATCO.NET
address:     San Martin, 638, 
address:     C1004AAN - Ciudad Autonoma de Buenos Aire - 
country:     AR
phone:       +54 11 43233360 []
created:     20060818
changed:     20140929

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.