131.158.136.0/21

NetHandle:      NET-131-158-0-0-1
OrgID:          DNIC
Parent:         NET-131-0-0-0-0
NetName:        USUHSNET
NetRange:       131.158.0.0 - 131.158.255.255
NetType:        assignment
RegDate:        1988-12-06
Updated:        2009-05-05
Source:         ARIN


OrgID:          DNIC
OrgName:        DoD Network Information Center
CanAllocate:    
Street:         3990 E. Broad Street
City:           Columbus
State/Prov:     OH
Country:        US
PostalCode:     43218
RegDate:        1970-01-01
Updated:        2011-08-17
OrgAbuseHandle: REGIS10-ARIN
OrgAdminHandle: MIL-HSTMST-ARIN
OrgTechHandle:  MIL-HSTMST-ARIN
OrgTechHandle:  REGIS10-ARIN
Source:         ARIN


POCHandle:      REGIS10-ARIN
IsRole:         Y
LastName:       Registration
FirstName:      
Street:         3990 E. Broad Street
City:           Columbus
State/Prov:     OH
Country:        US
PostalCode:     43218
RegDate:        2009-06-24
Updated:        2020-01-24
OfficePhone:    +1-844-347-2457
Mailbox:        disa.columbus.ns.mbx.arin-registrations@mail.mil
Source:         ARIN


POCHandle:      MIL-HSTMST-ARIN
IsRole:         Y
LastName:       Network DoD
FirstName:      
Street:         3990 E. Broad Street
City:           Columbus
State/Prov:     OH
Country:        US
PostalCode:     43218
RegDate:        1993-05-26
Updated:        2020-06-16
OfficePhone:    +1-844-347-2457
Mailbox:        disa.columbus.ns.mbx.hostmaster-dod-nic@mail.mil
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.