nslookup is a command-line tool used to query the Domain Name System (DNS) for information about domain names and their corresponding IP addresses. It's a valuable tool for network administrators and anyone interested in understanding how DNS works.
Here's how nslookup works:
- You enter a domain name: For example, you might type
nslookup google.com
. - nslookup sends a query: The tool sends a DNS query to a DNS server, usually the one configured on your system.
- DNS server responds: The DNS server receives the query, looks up the domain name in its database, and returns the corresponding IP address and other information.
- nslookup displays the results: The tool displays the results of the query, including the IP address, hostname, and other relevant information.
Here are some practical uses of nslookup:
- Verify DNS records: You can use nslookup to check if DNS records are correctly configured for a domain name.
- Troubleshoot DNS issues: If you're experiencing issues with DNS resolution, you can use nslookup to identify the source of the problem.
- Find IP addresses: You can use nslookup to find the IP address of a specific website or server.
- Learn about DNS servers: You can use nslookup to identify the DNS servers used by your computer or network.
Example:
C:\> nslookup google.com
Server: 192.168.1.1
Address: 192.168.1.1
Non-authoritative answer:
google.com canonical name = www.google.com.
www.google.com canonical name = www.l.google.com.
www.l.google.com canonical name = www.l.google.com.
www.l.google.com internet address = 172.217.160.142
In this example, nslookup first shows the DNS server used. Then, it displays the canonical name (CNAME) records for google.com
and www.google.com
, which are both resolved to www.l.google.com
. Finally, it shows the IP address of www.l.google.com
.