Powershell: Get FQDN Hostname

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}

Above line will print just the short name of the server

$sysinfo = Get-WmiObject -Class Win32_ComputerSystem
$server = “{0}.{1}” -f $sysinfo.Name, $sysinfo.Domain

Above two line will get me the FQDN but this looks really nasty code to retrieve just the hostname :(

So, My question is, is there an easier way to get the FQDN in powershell. I am a bash/perl coder and recently picked up powershell.. so finding it difficult.

Thanks.

[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...

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note: GetHostByName method is obsolete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]

[Win32_ComputerSystem Class]: <http://msdn.microsoft.com/en-us/library/aa394102%28v=vs.85%29.aspx>

[Dns Methods (System.Net)]: <http://msdn.microsoft.com/en-us/library/System.Net.Dns_methods%28v=vs.110%29.aspx>

"$env:computername.$env:userdnsdomain"

will work if separated out like this

"$env:computername"+"$env:userdnsdomain"

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...

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(".")

Here is a way to determine the FQDN of a server based on the "Name" and "DistinguishedName". Works for multiple domains:

$server = Get-ADComputer serverName -Server domainName -Properties * | select Name, DistinguishedName
$domain = $server.DistinguishedName -split ","
$domain = $domain | ? {$_ -like 'DC=*'}
$domain = $domain -join "."
$domain = $domain -replace "DC="
$FQDN = $server.Name + "." + $domain

I have the following add.. I need to separate out the dns suffix from the hostname.. and I only "know" the servers alias shortname... and want to know what the dns suffix is

#example:
#serveralias: MyAppServer.us.fred.com
#actualhostname: server01.us.fred.com
#I "know": "MyAppServer" .. I pass this on as an env var called myjumpbox .. this could also be $env:computername


$forname = $env:myjumpbox
$fqdn = [System.Net.Dns]::GetHostByName($forname).Hostname
$shortname = $fqdn.split('.')[0]
$domainname = $fqdn -split $fqdn.split('.')[0]+"."
$dnssuf = $domainname[1]
" name parts are- alias: " + $forname + " actual hostname: " + $shortname + " suffix: " + $dnssuf

#returns

name parts are- alias: MyAppServer actual hostname: server01 suffix: us.fred.com

To get FQDN of local computer:

[System.Net.Dns]::GetHostByName($env:computerName)

or

[System.Net.Dns]::GetHostByName($env:computerName).HostName

To get FQDN of Remote computer:

[System.Net.Dns]::GetHostByName('mytestpc1')

or

For better formatted value use:

[System.Net.Dns]::GetHostByName('mytestpc1').HostName

* For remote machines make sure host is reachable.

It can also be retrieved from the registry:

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