What is my fqdn linux

7 Linux Hostname Commands with Example | You should Know

The hostname is very important Linux command that you can find useful many times. If you are reading this article, for sure, you are using Linux system. Here you can get all the Linux hostname commands that you need to run every day.

Table of Content:

The host is nothing but your Linux system. And hostname is identity given to your system.

The hostname is useful when you want to connect your system to another system. To identify each system on the network, every system has been given hostname as identity. Hostname of the system is unique over the connected network.

Hostname command is used to get the system hostname as well as the DNS (Domain Name System) of the system.

Command hostname syntax:

Hostname command has its syntax.

The syntax for changing the hostname:

hostname [options] [new_host_name]

7 Linux Hostname Commands | You should know…

Each of the commands is explained in required detail for better understanding.

1. What is the command to find hostname in Linux?

Use the hostname command without any option.

It is also called as the domain name of the system.

2. What is the Linux command to get the IP address from hostname without ifconfig?

As I told you earlier, the hostname is unique over the connected network, there is corresponding IP address associated with hostname.

The hostname needs to resolve to get IP address which can be inferred from the hostname command along with -i and -I option.

You can also find the IP address of the Linux system using ifconfig . But, command ifconfig gives a large list of IP addresses. If you need only IP address you can just use hostname -i command. It’s easy.

3. How to get the DNS name of the system?

Use -d option to get the DNS name of the system.

Above command only give DNS name. It does not specify the exact location of the system in a hierarchy of DNS. To locate the exact location, you need a Fully qualified domain name (FQDN).

4. How to get the FQDN of the system?

Use -f option with hostname command.

This command will return the complete and exact location of the system in DNS hierarchy.
To see all the FQDN of the system use option -A .

5. How to get the alias name of the host?

There can be an aliased name for your hostname. Use -a flag with hostname command.

6. What is the Linux command to change hostname?

It is an easy and simple command.

You need super privilege for changing the hostname of the system.

If you try to get the IP address corresponds to the hostname, you may get some time error as…

hostname: Temporary failure in name resolution

Hostname command changes only persist until you reboot your Linux system.

7. How to make the hostname changes permanent?

There is a way to make the changes permanent if you wish.

Use a command hostnamectl .

You can explore and find more hostname commands using help option.

Hostname help command:

There are many other options you can use with hostname. You can get all the options by running a command hostname -h .

All the above-mentioned commands are tested on Ubuntu system and will work with any other Linux distribution.

That’s all from this quick post on Linux hostname command and examples. These are the very useful command related to the hostname. If you have any query related to the Linux command, let’s discuss in the comment.

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How to check fqdn in linux

If in your vhost is my-computer.my-domain.ext make sure to copy the exact name in /etc/hosts Caution: in the /etc/hosts file, the hostname and FQDN order must be respected. Solution 3: For further information about setting hostname and FQDN on debian (which also prevents the warning) check this: http://movealong.org/hostname.html

Check if the hostname is fully qualified (FQDN)

#!/bin/bash for h in "bert" "ernie" "www.google.com" do host $h 2>&1 > /dev/null if [ $? -eq 0 ] then echo "$h is a FQDN" else echo "$h is not a FQDN" fi done 

Like to insert the output of ‘hostname -f’ instead of ‘bert’ or www.google.com If the hostname is FQDN the script should continue, if not an error message should occur. PS. It is NOT important if the TLD exist or not. eg. hostname.domain is a FQDN or hostname.domain.tld is a FQDN. If the TLD is valid on the internet is not important to me. output of hostname -f

The usual way to ensure a hostname is fully-qualified is to specify the final . (that is usually omitted): example.com. .

However, from comments to the question, it appears that you want a simple string comparison — if a . appears anywhere, assume the name is valid, otherwise error. The simplest way is to compare the name against a copy with first . removed — if the two are identical, then there was no . to remove:

if [ "$h" != "$" ] then echo "$h is acceptable" >&2 else echo "$h is not acceptable" >&2 fi 

for h in "bert" "ernie" "www.google.com" do if [[ $ != "" ]] then echo "$h contains ." else echo "$h doesn't contain ." fi done 

Get IPv4 Address on Unix and Linux, Use Terminal to Get IPv4 Address on Unix and Linux. There are also many commands to get the IP address in the terminal, e.g., ip address, hostname -I, network manager. The command hostname -I will give you only the IP address on the terminal. The command ip address will give you a brief description of the IP …

How does Apache determine the FQDN?

I’m using Apache2, and when reloading/restarting the server I get this warning:

apache2: Could not reliably determine the server’s fully qualified domain name, using (my FQDN) for ServerName

Everything works fine, but I’m trying to figure out what’s causing the error. I’m grabbing the source to see if can find it, but since my C’s not very good.

• If I change the system hostname, Apache uses the new hostname
• I have a ServerName set; it’s the same as the hostname
• I have a static, unique IP — dig (hostname) returns (my ip), dig -x (my ip) returns (hostname)
• My hosts file is correct

Apache/2.2.9 Linux 2.6.24-23-xen x86_64 Description: Debian GNU/Linux 5.0 (lenny)

Are you sure you have a ServerName directive with the proper value — outside any blocks? (You also need a ServerName inside each block, of course)

When Apache gives out that error message, usually it means that it’s not finding a ServerName for the server as a whole. If you do have that directive set properly, I can’t imagine why Apache would still be complaining.

On Debian, the hostname is set at startup thanks to the script /etc/init.d/hostname.sh which uses the file /etc/hostname. We can use this file to update the computer hostname and its FQDN (fully qualified domain name).

If ServerName in your vhost is my-computer.my-domain.ext make sure to copy the exact name in /etc/hosts

Caution: in the /etc/hosts file, the hostname and FQDN order must be respected. First the fqdn then the hostname and localhost at the end.

~$ echo "my-computer" > /etc/hostname ~$ echo "127.0.0.1 my-computer.my-domain.ext my-computer localhost" > /etc/hosts ~$ /etc/init.d/hostname.sh 

You can check the change with the following lines:

~$ hostname my-computer ~$ hostname --fqdn my-computer.my-domain.ext 

The old hostname may still be present in the command line prompt. Just logoff then login to make it disappear.

For further information about setting hostname and FQDN on debian (which also prevents the warning) check this: http://movealong.org/hostname.html

How to Use the traceroute Command on Linux, Setting the traceroute Timeout Value. Perhaps if we extend the default timeout period (five seconds), we’ll get more responses. To do this, we’ll use the -w (wait time) option to change it to seven seconds. (Note this is a floating-point number.) We type the following command: traceroute -w 7.0 blarneycastle.ie.

Ip domain name/FQDN using dig

When I do a dig on a hostname, in our network, it doesn’t not give me the IP address, but when I add the domain name it does work or when I do a dig +search

Why is the domain name a prerequisite for DIG to resolve the hostname to IP?

Because dig is working as designed.

snip from man page:
+[no]search Use or do not use the search list defined by the search list or domain directive in the /etc/resolv.conf file (if any). The search list is not used by default.

In short, do not confuse dig with nslookup

Linux command line: find a host’s canonical hostname, You’ll have to log in and use the hostname command. If you’re looking for the Fully Qualified Domain Name (FQDN) of a network address, you can use DNS query tools like dig or nslookup, as described by @firm and @Richard Holloway. Share Improve this answer Follow answered Mar 16, 2010 at 11:07 mpez0 1,492 9 9 Add a …

Get VM Name and FQDN

Im trying to write a Powershell Query to get the VM Name & FQDM, this is what I have but its not returning the FQDN

Get-AzureRmVm | Select-Object Name , @> | Format-Table 

So I have been able to get the VM, and then the FQDN, and I feel its safe enough for me to do it this was because i know a single RSG will only even contain one VM and one FQDN, so its safe for me to assume they are linked.

Get-AzureRmVm | Foreach-Object | Select-Object ResourceGroupName, Name , Location , @> 

However it is slow because of the Foreach, wondered if anyone has any other suggestions on this.

When you create an Azure VM, a public IP resource for the VM is automatically created. Refer to this. None of FQDN is created for a VM in the Azure portal. You could configure it once the VM is created. You could not get the FQDN directly by using the AzureRM.Compute module since the FQDN or DNS name is not a property of VM but is a public IP address configuration.

You can get an FQDN of an Azure VM using

(Get-AzureRmPublicIpAddress -ResourceGroupName $rg -Name $publicipaddress ).DnsSettings.Fqdn 

Azure powershell — Get VM Name and FQDN, None of FQDN is created for a VM in the Azure portal. You could configure it once the VM is created. You could not get the FQDN directly by using the AzureRM.Compute module since the FQDN or DNS name is not a property of VM but is a public IP address configuration. You can get an FQDN of an Azure …

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