Powershell: Get FQDN Hostname

Question

I want to retrieve the FQDN name of windows server via powershell script. I have found 2 solution so far:

$server =  Invoke-Command -ScriptBlock {hostname}


        

Answer 1

[System.Net.Dns]::GetHostByName((hostname)).HostName

$env:computerName returns NetBIOS name of the host, so that both previous examples return netbioshostname.domainsuffix (not FQDN!) instead of dnshostname.domainsuffix (FQDN)

for example, host has FQDN aa-w2k12sv-storage.something.com and NetBIOS name aa-w2k12sv-stor (an easy case, I usually change NetBIOS name)

the hostname utility returns dnshostname, i.e., the first part of FQDN and code

[System.Net.Dns]::GetHostByName((hostname)).HostName

returns the right FQDN

Comment: never use the same NetBIOS and DNS names of AD domains and hosts. If your or 3rd party application writes to the log: "cannot connect to hostname.domainsuffix", what name it tries to resolve? If you see in the log "cannot connect to netbiosname.domainsuffix", no doubt, a lazy programmer added domain suffix to the NetBIOS name and you are sure, this is a bug, and can open a ticket to force them to fix the issue...

Answer 2

It can also be retrieved from the registry:

Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' |
   % { $_.'NV HostName', $_.'NV Domain' -join '.' }

Answer 3

Here's the method that I've always used:

$fqdn= $(ping localhost -n 1)[1].split(" ")[1]

Answer 4

Local Computer FQDN via dotNet class

[System.Net.Dns]::GetHostEntry([string]$env:computername).HostName

or

[System.Net.Dns]::GetHostEntry([string]"localhost").HostName

Reference:

Dns Methods (System.Net)

note: GetHostByName method is obsolete

---

Local computer FQDN via WMI query

$myFQDN=(Get-WmiObject win32_computersystem).DNSHostName+"."+(Get-WmiObject win32_computersystem).Domain
Write-Host $myFQDN

Reference:

Win32_ComputerSystem class

Answer 5

How about this

$FQDN=[System.Net.Dns]::GetHostByName($VM).Hostname.Split('.')
[int]$i = 1
[int]$x = 0
[string]$Domain = $null
do {
    $x = $i-$FQDN.Count
    $Domain = $Domain+$FQDN[$x]+"."
    $i = $i + 1
} until ( $i -eq $FQDN.Count )
$Domain = $Domain.TrimEnd(".")

Answer 6

I use the following syntax :

$Domain=[System.Net.Dns]::GetHostByName($VM).Hostname.split('.')
$Domain=$Domain[1]+'.'+$Domain[2]

it does not matter if the $VM is up or down...