First, run nslookup
against the domain to find the IP address it points to. Then run whois
against the IP address - this will tell you who IANA assigned the netblock the IP is in to. From there it is determining if it is a network provider, ISP, colocation company, etc.
Here's an example using google.com -
user@darkstar ~ $ nslookup google.com
Server: 192.168.1.2
Address: 192.168.1.2#53
Non-authoritative answer:
Name: google.com
Address: 172.217.3.238
user@darkstar ~ $ whois 172.217.3.238
#
# ARIN WHOIS data and services are subject to the Terms of Use
# available at: https://www.arin.net/whois_tou.html
#
# If you see inaccuracies in the results, please report at
# https://www.arin.net/resources/whois_reporting/index.html
#
NetRange: 172.217.0.0 - 172.217.255.255
CIDR: 172.217.0.0/16
NetName: GOOGLE
NetHandle: NET-172-217-0-0-1
Parent: NET172 (NET-172-0-0-0-0)
NetType: Direct Allocation
OriginAS: AS15169
Organization: Google LLC (GOGL)
RegDate: 2012-04-16
Updated: 2012-04-16
Ref: https://whois.arin.net/rest/net/NET-172-217-0-0-1
OrgName: Google LLC
OrgId: GOGL
Address: 1600 Amphitheatre Parkway
City: Mountain View
StateProv: CA
PostalCode: 94043
Country: US
RegDate: 2000-03-30
Updated: 2017-12-21
Ref: https://whois.arin.net/rest/org/GOGL
OrgTechHandle: ZG39-ARIN
OrgTechName: Google LLC
OrgTechPhone: +1-650-253-0000
OrgTechEmail: arin-contact@google.com
OrgTechRef: https://whois.arin.net/rest/poc/ZG39-ARIN
OrgAbuseHandle: ABUSE5250-ARIN
OrgAbuseName: Abuse
OrgAbusePhone: +1-650-253-0000
OrgAbuseEmail: network-abuse@google.com
OrgAbuseRef: https://whois.arin.net/rest/poc/ABUSE5250-ARIN
And one using serverfault.com - you can see the owner of the netblock is "Fastly Network Operations"
user@darkstar ~ $ nslookup serverfault.com
Server: 192.168.1.2
Address: 192.168.1.2#53
Non-authoritative answer:
Name: serverfault.com
Address: 151.101.193.69
Name: serverfault.com
Address: 151.101.129.69
Name: serverfault.com
Address: 151.101.1.69
Name: serverfault.com
Address: 151.101.65.69
user@darkstar ~ $ whois 151.101.65.69
#
# ARIN WHOIS data and services are subject to the Terms of Use
# available at: https://www.arin.net/whois_tou.html
#
# If you see inaccuracies in the results, please report at
# https://www.arin.net/resources/whois_reporting/index.html
#
NetRange: 151.101.0.0 - 151.101.255.255
CIDR: 151.101.0.0/16
NetName: SKYCA-3
NetHandle: NET-151-101-0-0-1
Parent: RIPE-ERX-151 (NET-151-0-0-0-0)
NetType: Direct Assignment
OriginAS:
Organization: Fastly (SKYCA-3)
RegDate: 2016-02-01
Updated: 2016-02-01
Ref: https://whois.arin.net/rest/net/NET-151-101-0-0-1
OrgName: Fastly
OrgId: SKYCA-3
Address: PO Box 78266
City: San Francisco
StateProv: CA
PostalCode: 94107
Country: US
RegDate: 2011-09-16
Updated: 2017-03-30
Ref: https://whois.arin.net/rest/org/SKYCA-3
OrgAbuseHandle: ABUSE4771-ARIN
OrgAbuseName: Abuse Account
OrgAbusePhone: +1-415-496-9353
OrgAbuseEmail: abuse@fastly.com
OrgAbuseRef: https://whois.arin.net/rest/poc/ABUSE4771-ARIN
OrgTechHandle: FRA19-ARIN
OrgTechName: Fastly RIR Administrator
OrgTechPhone: +1-415-404-9374
OrgTechEmail: rir-admin@fastly.com
OrgTechRef: https://whois.arin.net/rest/poc/FRA19-ARIN
OrgNOCHandle: FNO19-ARIN
OrgNOCName: Fastly Network Operations
OrgNOCPhone: +1-415-404-9374
OrgNOCEmail: noc@fastly.com
OrgNOCRef: https://whois.arin.net/rest/poc/FNO19-ARIN