Windows, DHCP Server Reservation - finding free IP address - windows

I'm trying to write up a script which would find (and later add reservation) for DHCP device. The problem I'm having that there is one scope, and within this scope we manually divided into different IP ranges where certain type of devices should be added.
E.g. the scope 10.92.0.0/24 and we assign ranges as
10.92.0.10-20 for iPhones etc.
10.92.0.10.50 for Android phones etc.
I've got the point where the script can go through the IP ranges I provide to it, and either GET DHCP reservation or show error. I've been thinking that first Error could be taken as the free IP.
Any ideas anyone? :)
# Get DHCP Scope
$Start = 100
$End = 140
$DHCPServer = "dhcpserver.company.com"
# Find Free IP address
#It can use to get DHCP reservation by IP and find the one which returns error - which can be used as the free one - loop done
#Now how to tell it to stop when the error occures?
While ($Start -le $End) {
$IP = "10.92.0.$Start"
Write-Host "Reservation for: $IP" -ForegroundColor Cyan
Get-DhcpServerv4Reservation -ComputerName $DHCPServer -IPAddress $IP
$Start++
}

Why don't you use the dedicated cmdlet Get-DhcpServerv4FreeIPAddress?
Get-DhcpServerv4FreeIPAddress -ScopeId "192.168.1.0" -StartAddress "192.168.1.100" -EndAddress "192.168.1.140" -ComputerName "dhcpserver.company.com"

You can assign the output of Get-DhcpServerv4Reservation to a variable, then act on that:
While ($Start -le $End) {
$IP = "10.92.0.$Start"
$reservation = Get-DhcpServerv4Reservation -ComputerName $DHCPServer -IPAddress $IP -ErrorAction SilentlyContinue
if($reservation){
Write-Host "Reservation for: $IP" -ForegroundColor Cyan
$reservation
}
else {
Write-Host "No reservation found for: $IP" -ForegroundColor Red
break #comment out to continue through all IPs in Scope
}
$Start++
}

Related

Logging off from all servers in a domain

Occasionally I forget to log off from a server or am disconnected through an error and I don't remember the name of the server. And my domain account starts getting periodically locked out, so I have to access logs on DC to find out which server(s) keep locking my account and log off from it/them. So I wanted to write to script in powershell that would log me off from all servers in a domain (with the exception of the server where I run the script on of course) without me needing to search which to log off from. This is what I have:
$ErrorActionPreference = "Silentlycontinue"
$Servers = (Get-ADComputer -Filter *).Name
$ScriptBlock = {
$Sessions = quser | ?{$_ -match $env:USERNAME}
if (($Sessions).Count -ge 1)
{
$SessionIDs = ($Sessions -split ' +')[2]
Write-Host "Found $(($SessionIDs).Count) user login(s) on $Server."
$SessionIDs | ForEach-Object
{
Write-Host "Logging off session [$($_)]..."
logoff $_
}
}
}
foreach ($Server in $Servers)
{
if ($Server -isnot $env:COMPUTERNAME)
{
Invoke-Command -ComputerName $Server -ScriptBlock {$ScriptBlock}
}
}
But when I launch the script, nothing happens. The script doesn't return any errors but doesn't log me off from any server, nor does it write any of the messages from Write-Host cmdlet, obviously. I noticed the $SessionIDs variable definition only returns ID of the first session. Usually this shouldn't be a problem, since it's unlikely I will have more than one session on a server, but I'd like to have this insurance. Can anyone tell me what's wrong in the script?
I notice a few things...
"First, I don't think quser | Where-Object {$_ -match $env:USERNAME} will ever return anything. The output of quser will not contain the hostname."
Try this for getting logon sessions:
$Sessions = (query user /server:$Env:ComputerName) -split "\n" -replace '\s\s+', ';' |
ConvertFrom-Csv -Delimiter ';'
Next, when you reference the $Server variable on the remote machine in your script block, it is out of scope. You would need to use $Using:Server in the script block.
Lastly, the -isnot operator doesn't compare value, it compares type. So in your last foreach, the if statement evaluates to "if type string is not type string" and will not run. Try -ne or -notlike instead.
Working with objects is much easier if you can just parse the output of QUser.exe. Given your scenario, here's my take on it:
$servers = (Get-ADComputer -Filter '*').Name.Where{$_ -ne $env:COMPUTERNAME}
foreach ($server in $servers)
{
if (-not ($quser = ((QUser.exe /server:$server) -replace '\s{20,39}',',,' -replace '\s{2,}',',' 2>&1) | Where-Object -FilterScript { $_ -match $env:USERNAME })) {
Continue
}
Write-Verbose -Message "$($quser.Count) session(s) found on $server." -Verbose
($quser.Trim() | ConvertFrom-Csv -Header 'USERNAME','SESSIONNAME','ID','STATE','IDLE TIME','LOGON TIME').foreach{
Write-Verbose -Message "Logging user [$($_.UserName)] off." -Verbose
LogOff.exe $_.ID /server:$server
}
}
Filtering should always happen before hand meaning, filter out your computer name on your first call to Get-ADComputer. Since you're using QUser.exe and LogOff.exe to begin with, I'd recommend the use of it all the way through since LogOff accepts an ID value that QUser outputs.
Next, placing the call to quser inside your if statement does two things in this case.
Filters for all users matching $ENV:UserName
Returns $true if anything is found, and $false if not found.
So, switching the results using -not will turn $false into $true allowing the execution of the code block which will just continue to the next server.
This in turn doesn't bother with the rest of the code and continues onto the next computer if no matching names were found.
The use of $quser inside the if statement is so you can save the results to it if more than one name is found; (..) allows this as it turns the variable assignment into an expression having the output pass through onto the pipeline where it is either empty, or not.
Finally, referencing the $quser variable we can convert the strings into objects piping to ConvertFrom-Csv. Only step left to do is iterate through each row and passing it over to LogOff to perform the actual logoff.
If you've noticed, the headers are manually-specified because it is filtered out by the Where-Object cmdlet. This is a better approach seeing as there could be "more than one" RDP Session, now you're just left with those sessions matching the name which can be saved to $quser, so no extra filtering is needed down the line.
So I modified the script this way and it works, sort of. It logs off account from servers, which is the main goal. There are still some glitches, like the message it sends from the first Write-Host doesn't give server's name, the message from second one gives a different value than it should (it gives [1] value after -split instead of [2] for some reason; but those are not really that important things, even though I will try to make at least the first message right) and $SessionIDs still gives only the first value, but usually you shouldn't have more than one RDP session per server. I've seen more sessions of one user, but that is very rare. But I'd also like to fix this if possible. Nevertheless, the script basically does the most important thing. But if someone has a suggestion how to fix the glitches I mentioned I would be grateful.
$ErrorActionPreference = "Silentlycontinue"
$Servers = (Get-ADComputer -Filter *).Name
$ScriptBlock = {
$Sessions = quser | ?{$_ -match $env:USERNAME}
if (($Sessions).Count -ge 1)
{
$SessionIDs = , ($Sessions -split ' +')[2]
Write-Host "Found $(($SessionIDs).Count) user login(s) on $Server."
Foreach ($SessionID in $SessionIDs)
{
Write-Host "Logging off session $SessionID..."
logoff $SessionID
}
}
}
foreach ($Server in $Servers)
{
if ($Server -ne $env:COMPUTERNAME)
{
Invoke-Command -ComputerName $Server -ScriptBlock $ScriptBlock
}
}

powershell script check internet connection then do if else

i wanna do a script which first checks the internet connection and if the computer has internet downloads a file. If the computer has no internet, the shell should write "You are not connected with the internet". The script does not work with
connection test-netconnection www.hawk.de -CommonTCPPort HTTP{}
My script is:
if() {
$client = new-object System.Net.WebClient
$client.Credentials = Get-Credential
$client.DownloadFile(“https://www.mydomain.de/sites/default/files/styles/xs_12col_16_9_retina/public/DSC_6947.JPG”,“C:\Users\Ole\Downloads\Github\bild.JPG”)
}else {
Write-Host "Could not connect to the Internet."
}
fi
Thanks for your help.
Try this for your if block..
IF (((Test-NetConnection www.site.com -Port 80 -InformationLevel "Detailed").TcpTestSucceeded) -eq $true)
Change the web address to suit obviously...
Windows tracks Internet connection status as part of Network Location Awareness; you can check this status using something like this:
If ((Get-NetConnectionProfile).IPv4Connectivity -contains "Internet" -or (Get-NetConnectionProfile).IPv6Connectivity -contains "Internet") {
# Do something here
}
https://learn.microsoft.com/en-us/windows/win32/winsock/network-location-awareness-service-provider-nla--2
You can use try..catch block for this:
try {
$client = new-object System.Net.WebClient $client.Credentials = Get-Credential $client.DownloadFile(“https://www.mydomain.de/sites/default/files/styles/xs_12col_16_9_retina/public/DSC_6947.JPG”,“C:\Users\Ole\Downloads\Github\bild.JPG”)
}
catch {
write-host "Not connected to the internet"
}
if..fi syntax refers to bash that's not powershell. Try..Catch is used to handle exceptions and errors.

Powershell Automation for Services

I have 100+ servers for which I have to check services. On almost 5 servers we have identical services. Each boxes contains min of 3 services.
I am importing content from the file I saved in a location. For Server name I am good. For Service I have saved like service_starting_name* in column under the file like below
AA*
BB*
CC*
Below is the code. Is this good idea for automation as per below code ?
$ServerName = Get-Content "Absolutepath"
$Service = Get-Content "Absolutepath"
foreach ($Server in $ServerName) {
write-host $($server)
Get-Service -ComputerName $Server $Service
}
Also , How can we do a better display like, without printing the service name ?
Suppose, In Server X , 5 services , so if all services are running just print all good on that server.
I tried using if conditions but as there are many services , it is printing multiple times because for for each loop .
Please suggest.
You can play around with various things..
For testing I use localhost, when you try:
Get-Service -ComputerName localhost -DisplayName *sophos*
You get:
(Get-Service -ComputerName localhost -DisplayName *sophos*).count
result 10
(Get-Service -ComputerName localhost -DisplayName *sophos*).Status -contains "stopped"
result True
So if you use:
if (!((Get-Service -ComputerName localhost -DisplayName *sophos*).Status -contains stopped)) { Write-Host "Localhost: All ok" }
Or:
if (!(Get-Service -ComputerName $server -DisplayName $Service | select status | where {$_.Status -like "Stopped"})) { Write-Host "$($Server): All OK" }
You can use various checks for services "stopping" or whatever..
The above are just to give you ideas!
Hope it helps.

get IPv4 address into a variable

Is there an easy way in PowerShell 3.0 on Windows 7 to get the local computer's IPv4 address into a variable?
Here is another solution:
$env:HostIP = (
Get-NetIPConfiguration |
Where-Object {
$_.IPv4DefaultGateway -ne $null -and
$_.NetAdapter.Status -ne "Disconnected"
}
).IPv4Address.IPAddress
How about this? (not my real IP Address!)
PS C:\> $ipV4 = Test-Connection -ComputerName (hostname) -Count 1 | Select IPV4Address
PS C:\> $ipV4
IPV4Address
-----------
192.0.2.0
Note that using localhost would just return and IP of 127.0.0.1
PS C:\> $ipV4 = Test-Connection -ComputerName localhost -Count 1 | Select IPV4Address
PS C:\> $ipV4
IPV4Address
-----------
127.0.0.1
The IP Address object has to be expanded out to get the address string
PS C:\> $ipV4 = Test-Connection -ComputerName (hostname) -Count 1 | Select -ExpandProperty IPV4Address
PS C:\> $ipV4
Address : 556228818
AddressFamily : InterNetwork
ScopeId :
IsIPv6Multicast : False
IsIPv6LinkLocal : False
IsIPv6SiteLocal : False
IsIPv6Teredo : False
IsIPv4MappedToIPv6 : False
IPAddressToString : 192.0.2.0
PS C:\> $ipV4.IPAddressToString
192.0.2.0
If I use the machine name this works. But is kind of like a hack (because I am just picking the first value of ipv4 address that I get.)
$ipaddress=([System.Net.DNS]::GetHostAddresses('PasteMachineNameHere')|Where-Object {$_.AddressFamily -eq "InterNetwork"} | select-object IPAddressToString)[0].IPAddressToString
Note that you have to replace the value PasteMachineNameHere in the above expression
This works too
$localIpAddress=((ipconfig | findstr [0-9].\.)[0]).Split()[-1]
Here are three methods using windows powershell and/or powershell core, listed from fastest to slowest.
You can assign it to a variable of your choosing.
Method 1: (this method is the fastest and works in both windows powershell and powershell core)
$ipAddress = (Get-NetIPAddress | Where-Object {$_.AddressState -eq "Preferred" -and $_.ValidLifetime -lt "24:00:00"}).IPAddress
Method 2: (this method is as fast as method 1 but it does not work with powershell core)
$ipAddress = (Test-Connection -ComputerName (hostname) -Count 1 | Select -ExpandProperty IPv4Address).IPAddressToString
Method 3: (although the slowest, it works on both windows powershell and powershell core)
$ipAddress = (Get-NetIPConfiguration | Where-Object {$_.IPv4DefaultGateway -ne $null -and $_.NetAdapter.status -ne "Disconnected"}).IPv4Address.IPAddress
Here is what I ended up using
$ipaddress = $(ipconfig | where {$_ -match 'IPv4.+\s(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' } | out-null; $Matches[1])
which breaks down as
execute ipconfig command - get all the network interface information
use powershell's where filter with a regular expression
regular expression finds the line with "IPv4" and a set of 4 blocks each with 1-3 digits separated by periods, i.e. a v4 IP address
disregard the output by piping it to null
finally get the first matched group as defined by the brackets in the regular expression.
catch that output in $ipaddress for later use.
(Get-WmiObject -Class Win32_NetworkAdapterConfiguration | where {$_.DHCPEnabled -ne $null -and $_.DefaultIPGateway -ne $null}).IPAddress
This one liner gives you the IP address:
(Test-Connection -ComputerName $env:computername -count 1).ipv4address.IPAddressToString
Include it in a Variable?
$IPV4=(Test-Connection -ComputerName $env:computername -count 1).ipv4address.IPAddressToString
Another variant using $env environment variable to grab hostname:
Test-Connection -ComputerName $env:computername -count 1 | Select-Object IPV4Address
or if you just want the IP address returned without the property header
(Test-Connection -ComputerName $env:computername -count 1).IPV4Address.ipaddressTOstring
tldr;
I used this command to get the ip address of my Ethernet network adapter into a variable called IP.
for /f "tokens=3 delims=: " %i in ('netsh interface ip show config name^="Ethernet" ^| findstr "IP Address"') do set IP=%i
For those who are curious to know what all that means, read on
Most commands using ipconfig for example just print out all your IP addresses and I needed a specific one which in my case was for my Ethernet network adapter.
You can see your list of network adapters by using the netsh interface ipv4 show interfaces command. Most people need Wi-Fi or Ethernet.
You'll see a table like so in the output to the command prompt:
Idx Met MTU State Name
--- ---------- ---------- ------------ ---------------------------
1 75 4294967295 connected Loopback Pseudo-Interface 1
15 25 1500 connected Ethernet
17 5000 1500 connected vEthernet (Default Switch)
32 15 1500 connected vEthernet (DockerNAT)
In the name column you should find the network adapter you want (i.e. Ethernet, Wi-Fi etc.).
As mentioned, I was interested in Ethernet in my case.
To get the IP for that adapter we can use the netsh command:
netsh interface ip show config name="Ethernet"
This gives us this output:
Configuration for interface "Ethernet"
DHCP enabled: Yes
IP Address: 169.252.27.59
Subnet Prefix: 169.252.0.0/16 (mask 255.255.0.0)
InterfaceMetric: 25
DNS servers configured through DHCP: None
Register with which suffix: Primary only
WINS servers configured through DHCP: None
(I faked the actual IP number above for security reasons 😉)
I can further specify which line I want using the findstr command in the ms-dos command prompt.
Here I want the line containing the string IP Address.
netsh interface ip show config name="Ethernet" | findstr "IP Address"
This gives the following output:
IP Address: 169.252.27.59
I can then use the for command that allows me to parse files (or multiline strings in this case) and split out the strings' contents based on a delimiter and the item number that I'm interested in.
Note that I am looking for the third item (tokens=3) and that I am using the space character and : as my delimiters (delims=: ).
for /f "tokens=3 delims=: " %i in ('netsh interface ip show config name^="Ethernet" ^| findstr "IP Address"') do set IP=%i
Each value or token in the loop is printed off as the variable %i but I'm only interested in the third "token" or item (hence tokens=3). Note that I had to escape the | and = using a ^
At the end of the for command you can specify a command to run with the content that is returned. In this case I am using set to assign the value to an environment variable called IP. If you want you could also just echo the value or what ever you like.
With that you get an environment variable with the IP Address of your preferred network adapter assigned to an environment variable. Pretty neat, huh?
If you have any ideas for improving please leave a comment.
I was looking for the same thing and figured this out:
$ip = Get-NetIPAddress -AddressFamily IPv4 -InterfaceIndex $(Get-NetConnectionProfile | Select-Object -ExpandProperty InterfaceIndex) | Select-Object -ExpandProperty IPAddress
This filters out both the loopback address and some virtual networks I have.
$ip = (Get-NetIPAddress -AddressFamily IPv4 -InterfaceIndex $(Get-NetConnectionProfile).InterfaceIndex).IPAddress
OR
function Get-LocalIP {
(
Get-NetIPAddress `
-AddressFamily IPv4 `
-InterfaceIndex $(
Get-NetConnectionProfile
).InterfaceIndex
).IPAddress
}
$ip = Get-LocalIP
To grab the device's IPv4 addresses, and filter to only grab ones that match your scheme (i.e. Ignore and APIPA addresses or the LocalHost address). You could say to grab the address matching 192.168.200.* for example.
$IPv4Addr = Get-NetIPAddress -AddressFamily ipV4 | where {$_.IPAddress -like X.X.X.X} | Select IPAddress
# Patrick Burwell's Ping Script - Patrick.Burwell#Infosys.com #
$Output= #() #sets an array
$names = Get-Content ".\input\ptd.pc_list.txt" #sets a list to use, like a DNS dump
foreach ($name in $names){ #sets the input by enumerating a text file to loop through and sets a variable to execute against
if ($IPV4 = Test-Connection -Delay 15 -ComputerName $name -Count 1 -ErrorAction SilentlyContinue|select IPV4Address #run ping and sets only IPV4Address response variable
){# If true then run...
$Output+= $Name,($IPV4.IPV4Address).IPAddressToString # Fills the array with the #true response
Write-Host $Name',','Ping,'($IPV4.IPV4Address).IPAddressToString -ForegroundColor Green #Sets the output to receive the Name, result and IPV4Address and prints the reply to the console with specific colors
}
else{#If false then run...
$Output+= "$name," #Fills the array with the #false response
Write-Host "$Name," -ForegroundColor Red #Prints the reply to the console with specific colors
}
}
#$Output | Out-file ".\output\result.csv" #<-- use to export to a text file (Set path as needed)
#$Output | Export-CSV ".\output\result.csv" -NoTypeInformation #<-- use to export to a csv file (Set path as needed)
#If you choose, you can merely have the reply by the name and IP, and the Name and no IP by removing the Ping comments
As I was working in Powershell 3, none of the answers here worked for me. It's based on Rob's approach, but this one works when you have multiple network adapters, it also picks out the IP correctly using capture groups
function GetIPConfig {
return ipconfig | select-string ('(\s)+IPv4.+\s(?<IP>(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}))(\s)*') -AllMatches | %{ $_.Matches } | % { $_.Groups["IP"]} | %{ $_.Value }
}
Non of the top comments are actually fully correct since a computer can have multiple interfaces and an interface can have multiple IP addresses. There are a few answers here which technically correct but utilizes "funky" ways to filter out wellknown addresses (like APIPA, localhost, etc) whereas even Powershell 3.0 have a native way to do so with PrefixOrigin.
$IPv4Addresses = $(Get-NetIPAddress | Where-Object { $_.PrefixOrigin -ne "WellKnown" -and $_.AddressFamily -eq "IPv4" }).IPAddress
I do this :
$interFaceAliasName="LAN" # You have to change the name according to your interface's name
$myInterface=(Get-NetIPAddress -InterfaceAlias $interFaceAliasName)
$myIP=$myInterface.IPv4Address
I recently had the same issue. So I wrote a script to parse it from the ipconfig /all output. This script is easily modifiable to obtain any of the parameters of the interfaces and it works on Windows 7 also.
Get output of IP config in LineNumber | Line format
$ip_config = $(ipconfig /all | % {$_ -split "rn"} | Select-String -Pattern ".*" | select LineNumber, Line)
Get list of interfaces (+ last line of ipconfig output) in LineNumber | Line format
$interfaces = $($ip_config | where {$_.Line -notmatch '^\s*$'} | where {$_.Line -notmatch '^\s'}) + $($ip_config | Select -last 1)
Filter through the interfaces list for the specific interface you want
$LAN = $($interfaces | where {$_.Line -match 'Wireless Network Connection:$'})
Get the start and end line numbers of chosen interface from output
$i = $interfaces.IndexOf($LAN)
$start = $LAN.LineNumber
$end = $interfaces[$i+1].LineNumber
Pick the lines from start..end
$LAN = $ip_config | where {$_.LineNumber -in ($start..$end)}
Get IP(v4) address field (returns null if no IPv4 address present)
$LAN_IP = #($LAN | where {$_ -match 'IPv4.+:\s(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'})
$LAN_IP = &{If ($LAN_IP.Count -gt 0) {$Matches[1]} Else {$null}}
$a = ipconfig
$result = $a[8] -replace "IPv4 Address. . . . . . . . . . . :",""
Also check which index of ipconfig has the IPv4 Address

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, $sysinfo.Domain
Above two line will get me the FQDN but this looks really nasty code to retrieve just the hostname :(
So, My question is, is there an easier way to get the FQDN in powershell. I am a bash/perl coder and recently picked up powershell.. so finding it difficult.
Thanks.
To get FQDN of local computer:
[System.Net.Dns]::GetHostByName($env:computerName)
or
[System.Net.Dns]::GetHostByName($env:computerName).HostName
To get FQDN of Remote computer:
[System.Net.Dns]::GetHostByName('mytestpc1')
or
For better formatted value use:
[System.Net.Dns]::GetHostByName('mytestpc1').HostName
For remote machines make sure host is reachable.
How about: "$env:computername.$env:userdnsdomain"
This actually only works if the user is logged into a domain (i.e. no local accounts), logged into the same domain as the server, and doesn't work with disjointed name space AD configurations.
Use this as referenced in another answer:
$myFQDN=(Get-WmiObject win32_computersystem).DNSHostName+"."+(Get-WmiObject win32_computersystem).Domain ; Write-Host $myFQDN
Local Computer FQDN via dotNet class
[System.Net.Dns]::GetHostEntry([string]$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
[System.Net.Dns]::GetHostByName((hostname)).HostName
$env:computerName returns NetBIOS name of the host, so that both previous examples return
netbioshostname.domainsuffix (not FQDN!)
instead of
dnshostname.domainsuffix (FQDN)
for example, host has
FQDN
aa-w2k12sv-storage.something.com
and NetBIOS name
aa-w2k12sv-stor (an easy case, I usually change NetBIOS name)
the hostname utility returns dnshostname, i.e., the first part of FQDN and code
[System.Net.Dns]::GetHostByName((hostname)).HostName
returns the right FQDN
Comment: never use the same NetBIOS and DNS names of AD domains and hosts. If your or 3rd party application writes to the log: "cannot connect to hostname.domainsuffix", what name it tries to resolve? If you see in the log "cannot connect to netbiosname.domainsuffix", no doubt, a lazy programmer added domain suffix to the NetBIOS name and you are sure, this is a bug, and can open a ticket to force them to fix the issue...
This worked in PS and PS Core on Windows (Tested on Versions 5.1 and 7.2)
[System.Net.Dns]::Resolve($null).HostName
(Get-ADComputer $(hostname)).DNSHostName
Here's the method that I've always used:
$fqdn= $(ping localhost -n 1)[1].split(" ")[1]
It can also be retrieved from the registry:
Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters' |
% { $_.'NV HostName', $_.'NV Domain' -join '.' }
to get the fqdn corresponding to the first IpAddress, it took this command:
PS C:\Windows\system32> [System.Net.Dns]::GetHostByAddress([System.Net.Dns]::GetHostByName($env:computerName).AddressList[0]).HostName
WIN-1234567890.fritz.box
where [System.Net.Dns]::GetHostByName($env:computerName).AddressList[0] represents the first IpAddress-Object and [System.Net.Dns]::GetHostByAddress gets the dns-object out of it.
If I took the winning solution on my standalone Windows, I got only:
PS C:\Windows\system32> (Get-WmiObject win32_computersystem).DNSHostName+"."+(Get-WmiObject win32_computersystem).Domain
WIN-1234567890.WORKGROUP
that's not what I wanted.
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...
If you have more than one network adapter and more than one adapter is active (f.e WLAN + VPN) you need a bit more complex check. You can use this one-liner:
[System.Net.DNS]::GetHostByAddress(([System.Net.DNS]::GetHostAddresses([System.Environment]::MachineName) | Where-Object { $_.AddressFamily -eq "InterNetwork" } | Select-Object IPAddressToString)[0].IPAddressToString).HostName.ToLower()
A cleaner format FQDN remotely
[System.Net.Dns]::GetHostByName('remotehost').HostName
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: " + $dnssuf
#returns
name parts are- alias: MyAppServer actual hostname: server01 suffix: us.fred.com
"$env:computername.$env:userdnsdomain"
will work if separated out like this
"$env:computername"+"$env:userdnsdomain"

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