Home
>
Web Hosting
>
Fun with DNS: Three Useful Commands

Fun with DNS: Three Useful Commands

The DNS is a distributed, hierarchical database where authority flows from the top (or root) of the hierarchy downward.

When thinking of the structure of the DNS, imagine an inverted tree. Each branch of the tree is within a zone of authority; however, multiple branches of the tree can be within a single zone.

The software (Bind being the most common) that stores domain name information is called a domain name server. A single name server can be authoritative for multiple zones. All zones have a primary master and a secondary master name server that provides authoritative responses for their zones.

If you query a name server not authoritative for a particular zone, that name server will most likely have up-to-date information. This is because zone information propagates throughout the Internet at regular intervals, and name servers cache zone information for which they are not authoritative.

DNS Commands

There are three crucial commands that can put all the DNS information you need at your fingertips. The way to use this article is to try each of the commands listed on a domain name, so you can see what the output looks like. Learn by doing!

Zone file database records divide DNS information into three primary types: NS (Name Server) records, MX (Mail Exchange) records, and A (Address) records. NS records indicate the name servers. MX records indicate the hosts that handle e-mail delivery; the priority (pri) number indicates the order in which mail servers are used, with the lowest number receiving the highest priority. The A (Address) records map hostnames to IP addresses, the real names of machines.

host

This is the simplest of the DNS commands. It is a quick way to determine the IP address of a hostname:

: host www.your-domain-name.com

The -a option will return all of the DNS information in verbose format.

: host -a www.your-domain-name.com

Now that you know the IP address for www.your-domain-name.com, try a reverse lookup.

: host IP-ADDRESS

dig (domain information groper)

This command gathers and returns DNS information in a format the name server can use directly. You will find it easy to query specific name servers with dig.

You can quickly determine the Name servers of your host or any other host:

: dig ns your-host.com

Then you check your (or another) website against the host's name servers:

: dig www.your-domain-name.com @ns.your-host.com

Dig can provide output that is in the same format as the zone file itself. Here is how to get the whole zone file:

: dig any your-domain-name.com

Here are the most useful dig query types: dig any (gathers all DNS information), dig ns (gathers name server information), dig mx (gathers mail exchanger information) and dig a (gathers network address information).

The dig command can also do reverse lookups with output formatted for the zone file:

: dig -x IP-Address

nslookup

You can use this tool as a single line command, or you can use it interactively, which distinguishes it from the other DNS commands. Once you have started nslookup, type set all to list the default options. As with dig you can choose the server (name server) you want to query, and you can decide the type of DNS information on which to focus.

Just as you can issue commands to nslookup interactively, you can also change the initial defaults by starting a .nslookuprc file. The format of the .nslookup is one command per line:

set type=NS
set domain=srvns.your-host.com
set timeout=10

Conclusion

These three commands can provide you with most of the information you need about your domain names. They are powerful tools, and this article should provide you enough information to get started or offer a quick refresher if you already use these commands.

About the Author:

Dan Forootan founded ez publishing, inc. in 1998. EZ Publishing's ez publishing, inc. provides the essential tools for using the Web as a marketing tool. The package includes web hosting, the ez publishing, inc. solution. Please email questions or comments about this article to ez publishing, inc.. Thank you.

green cleaning service Glencoe ..

In The News:

Fake buyers demand specific vehicle reports from unknown sites to steal credit card information from car sellers, but warning signs can help identify these scams before paying.

Android users can now manage apps across multiple devices more easily with Google Play Store's updated remote uninstall button in the latest update.

NASA's Perseverance rover discovers shiny metallic rock on Mars that could be a meteorite from an ancient asteroid, containing high levels of iron and nickel.

Holiday scams spike during Black Friday and Cyber Monday as criminals exploit your leaked personal data. Learn how to protect yourself from fake stores and phishing.

Commerce Department proposes TP-Link router ban over Chinese security risks. Learn how this potential prohibition could affect your home network and devices.

Hyundai AutoEver America suffered a data breach affecting 2,000 current and former employees, exposing names, Social Security numbers and driver's license information.

Washington court rules automated license plate reader images are public records, even when stored by vendors like Flock Safety, setting precedent for transparency.

Fake airline texts claiming flight cancellations are targeting travelers with convincing scams. Learn how cybercriminals steal personal data and credit card info.

Discover how iOS 26's new Adaptive Power feature automatically extends iPhone battery life by learning your usage patterns and adjusting performance intelligently.

New TikTok malware campaign tricks users into running PowerShell commands that download Aura Stealer, which steals credentials and authentication tokens.

Gaia Family offers fixed upfront pricing for IVF cycles with unlimited embryo transfers and financial protection, partnering with over 100 U.S. fertility clinics.

The Jetsons Act aims to position Pennsylvania as a leader in advanced air mobility by establishing regulations for hybrid ground-air vehicles.

Fake Geek Squad invoice emails are targeting users with convincing charges and urgent phone numbers to steal personal information and money.

Fox News Digital's artificial intelligence newsletter digs into a robot in Russia that faceplanted, George Clooney's alarm and OpenAI's rivalry with the New York Times.

Major data breach at Conduent exposes personal information of 10+ million people. Government contractor hit by cyberattack affecting Medicaid, child support systems.

Texas startup Janta Power raises $5.5M for innovative vertical solar towers that generate 50% more energy than traditional panels while using just one-third the land.

NASA's twin ESCAPADE spacecraft launched aboard Blue Origin's New Glenn rocket Thursday afternoon from Cape Canaveral, beginning their journey to Mars with arrival expected in 2027.

Learn how to set email reminders on iPhone and Android so you never forget to reply again. Simple built-in features help you stay organized and on top of messages.

Discover how Apple's passkeys revolutionize Mac security by replacing vulnerable passwords with biometric authentication and encryption for ultimate protection.

New survey reveals 78% of parents fear AI scams targeting their kids, yet nearly half haven't discussed these threats. Learn why this dangerous gap exists.

Chrome now autofills passport and driver's license info automatically. Google's latest browser update adds official document support with encryption and user control.

Scammers impersonate Department of Veterans Affairs employees claiming veterans owe money, but real VA communications only direct to VA.gov or official channels.

The AltoVolo Sigma hybrid-electric aircraft flies 500 miles at 220 mph while operating 80% quieter than helicopters, featuring safety systems and compact design.

Google search scam alert: fake customer service numbers can give scammers remote control of your phone. Learn how to spot these traps and protect yourself.

Electric vehicles overtake gas cars in total CO2 savings after just two years of driving, with emissions benefits growing over time as power grids get cleaner.

Fun with DNS: Three Useful Commands

Web Hosting