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.

ohare limo service Grand Rapids ..

In The News:

The International Olympic Committee on Friday announced plans to use AI in various Olympic aspects, including athlete identification, training and judging.

Tech guru Kurt "CyberGuy" Knutsson explains an easy trick to avoid squinting while working or surfing the web by zooming in on your personal computer.

Streaming giant Roku has recently been targeted by a pair of cyberattacks, and the company confirmed over a half million Roku accounts were compromised.

The Land Aircraft Carrier combines an all-terrain, six-wheeled vehicle with a two-seat aircraft, which features electric vertical takeoff and landing.

The European Union has sent TikTok a "request for information" on the video sharing platform's newest app, TikTok Lite, under the Digital Services Act, with the aim to clean up social media.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

The FBI is warning the public about a recent phishing scam via text that claims its targets owe money in Pennsylvania for unpaid road toll charges.

Your Apple Music settings may be revealing to your contacts what you're listening to. Kurt "CyberGuy" Knutsson explains the process to change those settings.

Learn how to secure social media accounts, implement legacy contacts, and create a digital estate plan to protect your online assets from 'ghost hackers' after your death.

A ported phone number scam is leading to more people having their identities stolen by sophisticated scammers. Kurt “CyberGuy" Knutsson tells you what you need to know.

The Great Pacific Garbage Patch, a vast marine debris vortex, is being tackled by The Ocean Cleanup’s innovative technologies. Kurt “CyberGuy" Knutsson explains.

Discover easy solutions to tame autocorrect frustration on iOS and Android devices. Turn off, customize and add personal touches to your typing experience.

Kurt “CyberGuy" Knutsson reveals the six top things to do right now before it’s too late: Tech and life choices that can keep your safer on and offline.

Kurt “CyberGuy" Knutsson shows you some simple steps to discreetly hide apps or an entire app page on your iPhone for decluttering or confidentiality.

The ambient light sensors on smartphones may be turned into cameras, according to researches at MIT. This could pose a threat to people's privacy.

The Autonomous Road Repair System from tech firm Robotiz3d uses artificial intelligence technology to locate potholes and promptly seal them.

Scammers have stooped to using artificial intelligence to scan obituary websites to create fake obituary websites to target the grieving.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

A Mercedes-Benz Manufacturing factory in Hungary is using humanoid robots to help with human staffing shortages on the factory floor.

Some video games act like unregulated banks, according to CFPB, which has begun monitoring the situation. The agency says children may be most at risk.

Ascender the robot is capable of climbing stairs with heights up to 8.7 inches, and it can give every corner of your home a deep cleaning.

Tax-return scams are on the rise, and one tax expert from a cybersecurity firm says filing your taxes on time is one way to avoid tax scams.

The innovative XPENG Robot Unicorn is inspired by the mythical unicorn, and you may forget the robot is not actually a living creature.

Stay up to date on the latest AI technology advancements and learn about the challenges and opportunities AI presents now and for the future.

The Federal Trade Commission, the federal agency to report scams to, is being impersonated as part of a new sophisticated phone scam.

Fun with DNS: Three Useful Commands

Web Hosting