What is the Host command?

The Host command is a software with a command-line interface that serves to test DNS. Internet Systems Consortium created it, and it is distributed as a permissive free software with an ISC license. 

As we mentioned already, the Host command is a utility tool for network diagnostic that you can use to probe different DNS records. You can see the A or AAAA records to get the IP address of a domain, see the name servers, find the start of authority, MX records, and more.

The purpose of the Linux Host command

The purpose of the Linux Host command is to query Domain Name System (DNS) servers to resolve domain names to IP addresses or vice versa. It is a command-line tool that can be used to retrieve DNS information about a hostname or domain, such as its IP address, aliases, or mail exchange (MX) records.

The Host command is a beneficial tool for developers and IT professionals who need to troubleshoot network issues or debug applications that rely on DNS. By using the Host command, they can quickly determine if a hostname is resolving to the correct IP address or if there are any issues with the DNS resolution process.

Additionally, the Host command can be used to perform advanced DNS queries, such as retrieving different types of DNS records and setting a specific timeout value. This makes it a versatile tool that can be used in various scenarios, from simple DNS lookups to more complex network debugging tasks.

Host command syntax

If you want to see the syntax of the Host command and the options that it has, you can simply write “host” and press “Enter.”

host [-aCdlnrsTwv] [-c class] [-N ndots] [-R number] [-t type] [-W time] [-m flag] [-4] [-6] hostname [server]

Host command Options

Here you can see all the available options. Whenever you forgot them, just write “host” in the Terminal.

Host command examples

For all the cases we will use Google.com. You can change Google.com with your domain or whichever else domain that you are interested in. We will give you several examples that can be useful for your work.

Search for the IP address of the domain.

host google.com

This command will show the content of the A and AAAA records. You will get IPv4 and IPv6 results for the domain.

SOA Record

See the Start of Authority records with this command. The SOA record is used for zone transfer. There could be only one SOA record per zone file. If you see more, then you need to fix the problem.

host –C google.com

Check the name servers of the domain

host –t ns google.com

It will display the name servers of the host. The –t, we use to specify the type of query. When you know all of the available name servers, you can test them individually. 

Check a particular name server

You want, for example, to review the ns1. To see if it is responsive or is there any problem, so you type:

host google.com ns1.google.com

 CNAME record

host –t cname mail.google.com

You can use it to find CNAME record. Those records will link one alias to the true name, the canonical. 

MX record

Check the incoming mail server with this query. You can see if they are responding correctly. 

host –n –t mx google.com

TXT Record

You can also check TXT records. There are various TXT DNS records that serve for authentication or verification. One of them is the SPF record that shows who can send emails from the particular domain. 

host –t txt google.com

Decide the Waiting time for a query

You can use –w to wait forever or –W and time in seconds to decide how long to wait for a reply.

host –T –W 10 google.com

Reverse lookup

You can also check the IP and see the host. It is a must to set the Reverse Lookup Zone for your mail server to work properly. 

host 216.58.194.142

Host command to see all of the DNS records for a domain

host –a google.com

You will get information about various types of records – NS, AAAA, MX, etc. With that report, later, you can probe each DNS individually. 

Change the default number of tries from 1 to the number you desire

host -R 8 google.com

In this example of host command, we changed from 1 to 8, the number of tries. The domain will have 8 chances to respond. When it manages to answer, it will stop the retries.   

-R : In order to specify the number of retries you can do in case one try fails. If anyone try succeeds then the command stops.

Troubleshooting Tips

When using the Linux Host command for DNS queries, you may encounter various issues. Here are some troubleshooting tips to help you resolve common problems:

• Domain does not resolve: If a domain doesn’t resolve, first ensure that the domain name is correctly spelled. Next, check your network connection and confirm that your DNS servers are set up correctly. Use other DNS tools like dig or nslookup for comparison. If the issue persists, it might be due to DNS propagation delays, which can take up to 48 hours after a DNS change.
• Interpreting error messages: Error messages can provide insights into what’s wrong. For example, “Host not found” suggests the domain name does not exist or DNS propagation has not completed. “Connection timed out” indicates a problem reaching the DNS server, possibly due to network issues or incorrect DNS server settings.
• DNS propagation delays: After DNS changes, it can take time for the updates to propagate through the internet’s DNS system. Use tools like whois or online DNS checkers to see if your changes have propagated. Patience is key here, as this process is beyond your direct control.

Alternatives to the Host command

There are several alternative DNS probing tools that you can use in place of the Host command, and some of the most popular ones include:

• Nslookup command: This tool is available on Linux, macOS, and Windows, and is straightforward to use. It’s a reliable, always-on-hand option for DNS lookups.
• Dig command: Some users prefer this tool over Host as it has additional options and can retrieve all types of DNS records.
• Ping command: While not as comprehensive as other tools, this network utility is useful for checking host availability by sending packets to a host or IP address to see how it responds.

Exploring and learning to use various DNS probing tools is great. Having multiple options on hand can be beneficial, especially if you manage multiple sites or need to troubleshoot different types of network issues.

Conclusion:

This was the Host command. Now you have one more way to troubleshoot your DNS. If you are interested in diagnostic tools, we recommend you the following articles too: Dig command, Nslookup, Traceroute, MTR and Ping. They will expand your knowledge in DNS diagnostic.

The post Linux Host command, troubleshot your DNS appeared first on ClouDNS Blog.

However, like every other IT problem, DNS issues can be resolved. You just have to know the right tools and commands. In this blog post, we’ll delve into some of these essential DNS troubleshooting tools and commands that every network administrator ought to arm themselves with.

Common DNS Issues 

Before we dive into the tools and commands, let’s understand the most common DNS issues that most administrators often encounter:

1. DNS Downtime: This occurs when DNS servers that translate domain names are temporarily unavailable.
2. Incorrect DNS Configuration: This involves errors in the setup of DNS settings which may lead to problems accessing certain websites or the internet.
3. DNS Cache Poisoning: Also known as DNS Spoofing, it refers to fraudulent entries in the DNS cache, causing traffic to be directed to the wrong place.
4. DNS Propagation Delays: This happens when you make changes to your DNS records and they are not immediately effective due to the time taken to update network servers around the globe.

Now that we have a basic understanding of common DNS issues, let’s explore the essential DNS troubleshooting commands that can help you diagnose and resolve these problems.

DNS Troubleshooting Tools

There are plenty of tools that you can use. The tools can be specific for Linux, Windows, or Mac OS, or they can be browser-based. Most of the tools that we will show you overlaps in functionality, and it will be your decision which one you would use in the future.

Check if the problem is not just in your device

Before you start with the DNS troubleshooting, check if the problem is only local. If you are trying to access your website, but you are getting this message “DNS_PROBE_FINISHED_NXDOMAIN” the problem might be in your device. We recently wrote a way to fix it. Go and read the article. 

Dig command

The ‘dig’ command, which stands for ‘Domain Information Groper,’ is a handy command-line tool used in the DNS name resolution process. It sends a DNS query to a specified DNS server and gets a response. It’s a useful tool for finding DNS-related issues. 

With this command you can see all the DNS records. You can use it on Linux and Mac OS, but you can search for a port for Windows too. A typical dig command will show you an Authority Section. You can see if the DNS is pointing correctly.

Use it with +trace in dig +trace combination “dig +trace YOURDOMAIN” to see the whole route of your query. This way you can locate the exact problem.

ClouDNS Free DNS tool

ClouDNS brings to you a valuable Free DNS tool that has transformative capabilities to enhance your DNS troubleshooting tactics. With this tool, you can inspect the DNS records for a specific host and assess the speed of DNS queries. Aside from these, you can also create a comprehensive audit, a feature that helps in in-depth analysis and identification of problematic areas.

Designed to facilitate the work of their customers, the ClouDNS Free DNS tool is user-friendly and accessible, making DNS troubleshooting a breeze even for beginners in the field. All you need to do is enter your domain and host into the tool, select the tool type as “DNS Records”, and choose ‘Google’ as your DNS resolver, then hit ‘CHECK’. 

What’s more, this powerhouse tool is free of cost, making it a stellar choice for efficient network management. The value it provides, particularly in terms of insight into DNS records and query speed, can go a long way in troubleshooting DNS-related problems swiftly and effectively.

Traceroute

The ‘traceroute’ command enables you to track the pathway that a packet takes from the host to the destination server. As the name suggests, this will be ideal for checking the entire route of a DNS query. You can use it on Windows as Tracert, Linux and Mac OS as traceroute. You can try it with a domain or IP address, and you will see a result with all the hops and response time.

NSLookup

‘NSLookup‘ stands for ‘Name Server Lookup’. This command-line tool is used for obtaining information about DNS settings. It allows users to enter a host name and find out the corresponding IP address, or vice versa.

This command lets you check any type of DNS record. You can use it to see all the available DNS records, or you can look for a specific type like – A, AAAA, SOA, MX, PTR, NS, etc. You can use it to troubleshoot a domain using a particular port too. 

Host command

‘Host’ command is very similar to the NSLookup but available only on Linux. You have to write the commands in the Terminal, and you can see the different types of DNS records.

One thing that you can troubleshoot if you have problems with your emails are the TXT records. You can see if there is a SPF record. It is a TXT record that prevents spoofing and stops your outgoing emails from going directly into the spam folder.

Generate SPF record for free!

Conclusion

There are plenty of useful tools that you can use for DNS troubleshooting. Try all of these and find the right one for you and your problem. Many overlaps in functionality, but have some small differences that can help you in a specific case.

As you saw, there are utilities for every operating system so that you can find the problem easily. After you see where the problem is, it is easy to fix it.  

The post DNS Troubleshooting – tools and commands appeared first on ClouDNS Blog.