Frequently Used Network Commands
Nslookup is a command-line tool to obtain domain names or IP addresses mapping, or other specific DNS Records. The name “nslookup” means “name server lookup”.
Find the A record of а domain
The ip address for yahoo.com is 220.127.116.11. You are querying the DNS server 2607:f720:100:100::230. If you can’t load a website by typing its ip, look at this article
$ nslookup -type=a yahoo.com Server: 2607:f720:100:100::230 Address: 2607:f720:100:100::230#53 Non-authoritative answer: Name: yahoo.com Address: 18.104.22.168 Name: yahoo.com Address: 22.214.171.124 Name: yahoo.com Address: 126.96.36.199 Name: yahoo.com Address: 188.8.131.52 Name: yahoo.com Address: 184.108.40.206 Name: yahoo.com Address: 220.127.116.11
Reverse DNS Lookup
Reverse DNS lookups for IPv4 addresses use the special domain in-addr.arpa.
$ nslookup 18.104.22.168 Server: 2607:f720:100:100::230 Address: 2607:f720:100:100::230#53 Non-authoritative answer: 22.214.171.124.in-addr.arpa name = media-router-fp2.prod1.media.vip.gq1.yahoo.com. Authoritative answers can be found from: 246.137.98.in-addr.arpa nameserver = ns2.yahoo.com. 246.137.98.in-addr.arpa nameserver = ns3.yahoo.com. 246.137.98.in-addr.arpa nameserver = ns1.yahoo.com. 246.137.98.in-addr.arpa nameserver = ns5.yahoo.com. 246.137.98.in-addr.arpa nameserver = ns4.yahoo.com. ns1.yahoo.com has AAAA address 2001:4998:130::1001 ns2.yahoo.com has AAAA address 2001:4998:140::1002 ns3.yahoo.com has AAAA address 2406:8600:f03f:1f8::1003 ns5.yahoo.com has AAAA address 2406:2000:ff60::53 ns1.yahoo.com internet address = 126.96.36.199 ns2.yahoo.com internet address = 188.8.131.52 ns3.yahoo.com internet address = 184.108.40.206 ns4.yahoo.com internet address = 220.127.116.11 ns5.yahoo.com internet address = 18.104.22.168
Find the NS records of a domain
The name server address for yahoo.com is ns3.yahoo.com. You are querying the DNS server 2607:f720:100:100::230.
$ nslookup -type=ns yahoo.com Server: 2607:f720:100:100::230 Address: 2607:f720:100:100::230#53 Non-authoritative answer: yahoo.com nameserver = ns3.yahoo.com. yahoo.com nameserver = ns5.yahoo.com. yahoo.com nameserver = ns4.yahoo.com. yahoo.com nameserver = ns1.yahoo.com. yahoo.com nameserver = ns2.yahoo.com. Authoritative answers can be found from: ns1.yahoo.com has AAAA address 2001:4998:130::1001 ns2.yahoo.com has AAAA address 2001:4998:140::1002 ns3.yahoo.com has AAAA address 2406:8600:f03f:1f8::1003 ns5.yahoo.com has AAAA address 2406:2000:ff60::53 ns1.yahoo.com internet address = 22.214.171.124 ns2.yahoo.com internet address = 126.96.36.199 ns3.yahoo.com internet address = 188.8.131.52 ns4.yahoo.com internet address = 184.108.40.206 ns5.yahoo.com internet address = 220.127.116.11
traceroute command prints the route that a packet takes to reach the host. This command is useful when you want to know about the route and about all the hops that a packet takes. If seeing *** in traceroute, it means that a packet is not acknowledged within the expected timeout.
$ traceroute googl.com traceroute to googl.com (18.104.22.168), 64 hops max, 52 byte packets 1 100.81.32.2 (100.81.32.2) 2.545 ms 4.359 ms 2.308 ms 2 preuss-6509-nodeb-dist-6509-ge.ucsd.edu (22.214.171.124) 2.099 ms 2.057 ms 2.194 ms 3 mx0--nodem-core-30ge.ucsd.edu (126.96.36.199) 1.996 ms 2.933 ms 2.057 ms 4 dc-sdg-agg4--ucsd-100ge.cenic.net (188.8.131.52) 2.567 ms 3.171 ms 3.231 ms 5 tus-agg8--sdg-agg4-3x100ge.cenic.net (184.108.40.206) 5.169 ms 5.294 ms 5.395 ms 6 lax-agg6--tus-agg8-100g-3.cenic.net (220.127.116.11) 4.850 ms dc-lax-agg6--tus-agg8-100ge-1.cenic.net (18.104.22.168) 11.178 ms 4.658 ms 7 22.214.171.124 (126.96.36.199) 4.803 ms 5.075 ms 5.444 ms 8 188.8.131.52 (184.108.40.206) 6.112 ms 5.003 ms 5.069 ms 9 220.127.116.11 (18.104.22.168) 4.707 ms 22.214.171.124 (126.96.36.199) 4.704 ms 188.8.131.52 (184.108.40.206) 4.988 ms 10 lax28s15-in-f4.1e100.net (220.127.116.11) 4.700 ms 4.645 ms 4.568 ms
WHOIS returns information about the registered Domain Names, an IP address block, Name Servers and a much wider range of information services.
How to Find IP Address Information
How to Find Domain Information
~$ whois google.com Domain Name: GOOGLE.COM Registry Domain ID: 2138514_DOMAIN_COM-VRSN Registrar WHOIS Server: whois.markmonitor.com Registrar URL: http://www.markmonitor.com Updated Date: 2019-09-09T15:39:04Z Creation Date: 1997-09-15T04:00:00Z Registry Expiry Date: 2028-09-14T04:00:00Z Registrar: MarkMonitor Inc. Registrar IANA ID: 292 Registrar Abuse Contact Email: email@example.com Registrar Abuse Contact Phone: +1.2083895740 Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited Domain Status: serverDeleteProhibited https://icann.org/epp#serverDeleteProhibited Domain Status: serverTransferProhibited https://icann.org/epp#serverTransferProhibited Domain Status: serverUpdateProhibited https://icann.org/epp#serverUpdateProhibited Name Server: NS1.GOOGLE.COM Name Server: NS2.GOOGLE.COM Name Server: NS3.GOOGLE.COM Name Server: NS4.GOOGLE.COM DNSSEC: unsigned URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/ ... ...