The application known as “nslookup” enables any computer user or Internet server administrator to enter a host name (for instance, “whatis.com”) and discover the related IP address or domain name system (DNS) record. Additionally, the user can submit a command to perform a reverse DNS lookup and discover the host name for a given IP address.
Nslookup is utilised for security purposes or to troubleshoot server connections. These include preventing phishing attempts, in which a domain name is changed to make a malicious site appear trustworthy and familiar, such as by changing the number 1 to a lowercase l. (joes1owerprices.com vs. joeslowerprices.com).
In order to disseminate data to caching resolvers while appearing as an authoritative origin server, a technique known as cache poisoning, DNS, or nslookup, is used.
DNS query using Linux
Other details connected to the host name or IP address, like related mail services, can be found using Linux and other nslookup versions. Some UNIX-based operating systems include nslookup. The ping command is a more constrained substitute for nslookup for seeking up an IP address.
How do I utilise the Windows-integrated nslookup tool?
You can use the command prompt to access the NSLOOKUP utility that is part of Microsoft Windows. You can use this tool to monitor DNS record propagation and resolution across various servers and carry out additional troubleshooting operations.
To launch the command prompt, go to Start and type cmd into the search bar. Alternatively, select Start > Run and enter command or cmd.
Enter the nslookup command. The IP address of your personal DNS server will be displayed. The type of record, domain name, and DNS server (IP address) can all be specified.
The command will return the A record for the domain you run a query for when you type nslookup and the domain name.
Enter nslookup -q=XX, where XX is a DNS record type. The types that are offered include MX, A, CNAME, and TXT. After the records are shown, type quit to leave the tool.
By using the -type=record type option with record type being one of A, CNAME, MX, PTR, NS, or ANY, you can specify the precise type of record to lookup for a domain when using nslookup as a troubleshooting tool.
Hit Enter after entering nslookup -type=ns domain name, where domain name is the domain for your search.
The name servers for the domain you specified are now displayed by the programme.
Nslookup: Why Use It?
This process of resolving a domain name takes multiple phases, yet it is completed in less than a second. The majority of the time it works, but you need to understand why when it doesn’t. In this situation, nslookup is useful.
Using the command-line programme nslookup, you can discover the host’s IP address or vice versa. This can be used on Windows, Unix, or even online using programmes like centralops.net and ping.eu.
Having these choices is crucial because if DNS isn’t functioning properly, you won’t be able to send emails, browse websites, or utilise chat services. Business may slow down or possibly stop in these circumstances, therefore you must find a swift solution. You obtain a simple method for troubleshooting and restoring service by using nslookup.
DNS Monitoring Considerations
While monitoring DNS to measure speed and uptime is vital, nslookup is a useful technique to troubleshoot DNS. This increases your network’s visibility and improves your coverage of any issues.
When observing DNS, pay attention to the following areas:
Records in NS
This verifies that IP addresses haven’t been modified with in the name server’s primary and backup records:
If the MX and SRV records for the IP addresses do not match, you will be informed by the following:
This is essential to maintaining the functionality of your email services.
However, because this form of monitoring is challenging, it is preferable to use a DNS monitoring tool. A decent tool will provide you with further data and analysis to safeguard your DNS.
How to Fix DNS Resolution Problems
We will learn how to troubleshoot DNS in this section if DNS resolution isn’t working.
1. Verify the network connection
You should first examine your network connectivity.
Open the Network and Sharing Center and select the Ethernet connection to check the network connections. The screen that follows should appear:
You ought to notice a reliable, live internet connection here.
2. Check the connectivity of your DNS server
The next step is to locate the IP address of your DNS server and determine whether it can be reached.
Open the Network and Sharing Center, select the Ethernet connection, and then click the Details icon to reveal the DNS IP address. The screen that follows should appear:
You should be able to see that the IP addresses of your DNS servers are 100.100.2.136 and 100.100.2.138 on the screen above.
Let’s now launch the command-line interface (Start > RUN > type cmd and press Enter) and execute the ping command as displayed below to verify the DNS server connectivity:
You should be able to see on the screen above that your machine can access the DNS server.
All visited URLs, IP addresses, and resource entries are kept in the DNS cache.
It is advised that you empty the DNS cache sometimes because using an out-of-date DNS cache can result in DNS resolution issues.
Run the following command on your command line interface to clear the DNS cache.
For more details and instructions, see IhowD.