Script to ping multiple hosts and return if the IP corresponds to the correct host

Question

Script to ping multiple hosts and return if the IP corresponds to the correct host

Jairon Junior 21

Hey there, wonder if anyone can help me, I'm currently new to the area, so I really don't know much about it, i'm looking for a way to make my job easier, I'm currently needing to ping a lot of machines so when it's on I can run some tasks, the problem is that on the list I'm currently working on has a lot of duplicated dns machines, so the host returns as ON, but it's in fact other machine, would appreciate if while pinging the hosts it would do something like a (ping -a to the ip) so I would know for sure i'ts the correct host. Please forgive my confusing english, it's pretty rusty nowadays @_@.
The script i'm currently using is the following, if possible would be awesome if someone could add the function in it, thanks!!!

$Output= @()

$names = Get-Content ".\ip4.txt"

foreach ($name in $names){

if (Test-Connection -Delay 15 -ComputerName $name -Count 1 -ErrorAction SilentlyContinue){

$Output+= "$name"

Write-Host "$Name" -ForegroundColor Green

}

else{

$Output+= "$name"

Write-Host "$Name" -ForegroundColor Red

}

$Output | Out-file ".\result.csv"

Accepted answer

4 additional answers

Your answer

Answer 1

Rich Matheisen 47,901

See if this works for you:

Get-Content ".\ip4.txt" |
    ForEach-Object{
        $result = [ordered]@{
                    DNSName     = $_.Trim()
                    HostName    = ""
                    DNSIPv4     = ""
                    Up          = ""
                    TestedIPv4  = ""
                    }
        Try{
            $entry = [System.Net.Dns]::GetHostEntry($_.Trim())
            $result.HostName = $entry.HostName
            $entry.AddressList |
                Where-Object {$_.AddressFamily -eq 'InterNetwork'} |
                    ForEach-Object{
                        $result.DNSIPv4 = $_.IPAddressToString
                        [array]$x = Test-Connection -Delay 15 -ComputerName $result.DNSName -Count 1 -ErrorAction SilentlyContinue
                        if ($x){
                            $result.Up = "Yes"
                            $result.TestedIPv4 = $x[0].IPV4Address
                        }
                        else{
                            $result.Up = "No"
                            $result.TestedIPv4 = "N/A"
                        }
                    }
        }
        Catch{
            $result.HostName = "Host Unknown"
            $result.Up = "Unknown"
            $result.TestedIPv4 = "N/A"
        }
        [PSCustomObject]$result
    }

You can pipe the results to Export-Csv or Format-Table. There's no red or green, but you can get what you need from a CSV and select or sort as you like.

Jairon Junior 21 Reputation points

2022-01-13T11:45:48.807+00:00

Thanks for dedicating your time to help me, so it's an awesome script is showing a lot of stuff that is going to help, but the problem itself persist, forgive me for not having the technical knowledge to express it in a way you guys would understand right a way. There's currently like trash on the dns manager, when theres like 4 different computers on the same ip for example:

Computer1 192.168.0.2 10/09/21
Computer2 192.168.0.2 11/10/21
Computer3 192.168.0.2 10/01/22
Computer4 192.168.0.2 12/01/22

so when I run the script for computer 1, it says that the computer is UP, but actually it's communicating with the computer4, your script will show me like

DNSName : computer1
HostName : computer1.xxxxxx.local
DNSIPv4 : 192.168.0.2
Up : Yes
TestedIPv4 : 192.168.0.2

but when I open CMD and run (Ping -a 192.168.0.2) the Ipv4 that currently say that's UP, is responding to computer4, so I can't run the task I need to, because it will run on the wrong computer, you get me?
The only one thing left that would save my life is a line on this same script you sent me, that would tell me the resulting host responding to that ipv4 address, something like

DNSName : computer1
HostName : computer1.xxxxxx.local
DNSIPv4 : 192.168.0.2
Up : Yes
TestedIPv4 : 192.168.0.2
actual computer: computer4.xxxxx.local

I know, you did like everything I just needed to add what I needed on the script, but I really never worked with it, tried to read it so I could edit it but pff, no chance
Rich Matheisen 47,901 Reputation points

2022-01-13T15:20:30.157+00:00

Stating what the problem is the correct thing to do. However, I don't think that what you're trying to accomplish is going to be solved by a one-and-done cleansing of your DNS.

Are you dolling out IP addresses using DHCP? Or are the machines assigned static IP addresses? Are the machines allowed to register their IP addresses in DNS? Do the DNS entries show that the computer accounts have permission to modify the entries?

Does DHCP have permission to modify the DNS entries?

Your problem is rooted, I think, as a minimum, in an incorrect configuring of DHCP. The way the client machines are acting is also something you need to invertigate.
Jairon Junior 21 Reputation points

2022-01-13T18:27:49.62+00:00

Yea, there's a problem with the DNS, theres a lot of old adresses there, some desktop's doesn't even exist, but the guy responsible for it is on vacation, so while he isn't here, i'm doing the ones that are currently available, in some cases I can delete the duplicated desktops on the DNS and ask for the user to restart the computer, but like I said, i'm doing to many computers right now, would be a pain to try to fix it, so I need something to make my life easier, so I dont need to ping back the ip address to check if it corresponds to the correct host

Answer 2

Michael Taylor 60,161

Well it seems like you are actually wanting to do 2 different things: a) ping to verify a machine is available, and b) get the DNS name that goes with the IP address you're pinging. Definitely doable with the ping command but parsing that output isn't my favorite option so I'd personally break it up into 2 steps. Firstly I'd get the DNS name given the IP address (if any) and then I'd ping the machine to verify it is online. Perhaps something like this.

$addresses = Get-Content ".\ip4.txt"
foreach ($address in $addresses) {
   $entry = [System.Net.Dns]::GetHostEntry($address)
   if ($entry -and Test-Connection -delay 15 -computername $entry.HostName -count 1 -ErrorAction SilentlyContinue) {
      $Output += $entry.HostName
   }
}

HostName has the DNS name as defined by the DNS resolution.

Jairon Junior 21 Reputation points

2022-01-12T19:41:10.367+00:00

Thanks for your answer, I didn't test it yet, but what I do is, I run the script I got above, and the online machines it shows the host name in the color green, then those hosts i move to a different txt file, so there's only online machines there, then what I do is ping individually each machine, and the ip that shows I ping with the "ping -a" so I can be certain that the host and the ping are responding to the same machine, but the problem is, the first part is really fast because the script does it for me, but then do manually for like 30 machines to know if they all are in the correct ip is kinda annoying, hope you get what I meant lol, and thanks i'll try to understand the script and see If i can run it
Michael Taylor 60,161 Reputation points

2022-01-12T19:49:13.397+00:00

The script I gave will load your IP4 file which I assume contains IP addresses. For each one it gets the DNS name and then pings the remote machine using the DNS name. If successful then it adds the DNS name to your $Output variable. So this will confirm that the IPs given in your file can be pinged by using their corresponding DNS names, if any.
Jairon Junior 21 Reputation points

2022-01-12T19:57:41.047+00:00

It's the desktop, laptop names actually like D-F12-037434, L-F12-034312 etc etc, then in the powershell script it shows the host names in green if up and red if down, doesnt show the IP itself
Michael Taylor 60,161 Reputation points

2022-01-12T20:40:54.62+00:00
OK so you have the DNS name and you want the IP addresses. In that case the code remains the same. But a single DNS name can map to multiple IP addresses so the AddressList array contains the IP address(es) that the machine has. Going back to your manual process it sounds like you ping by host name to get the IP. Then you ping by IP to get the host name. This seems like it isn't really verifying anything extra to me as pinging by host name is just going to look up the IP address and ping that. Pinging by IP is going to return a host name that may or may not line up with what you expected given that a machine can have multiple DNS records.

How about this, use the earlier code to get the IP address(es) of the host name. Then ping the host to get the IP address. Now compare the IP address returned from ping to the IP address(es) contained in DNS. I'm not sure it proves what you're aiming for though.

$ping = New-object 'System.Net.NetworkInformation.Ping' $addresses = Get-Content ".\ip4.txt" foreach ($address in $addresses) { $entry = [System.Net.Dns]::GetHostEntry($address) if ($entry) { $pingResult = $ping.Send($entry.HostName) if ($pingResult.Status -eq 'Success' -and $entry.AddressList -match $pingResult.Address) # Pinged machine and returned IP is in the list of IPs for the given DNS name } }
Jairon Junior 21 Reputation points

2022-01-13T11:50:47.173+00:00

RichMatheisen script is getting there, is just a line that's missing, I tried to explain there, I tried to run your script but I didn't work, as a extremly newbie person, I presume you were showing me what I need, but I would need to implement it on the script I was working with? the problem is that I really not understand it, maybe on the future when had classes of it, or just learned by working with it, i'll remember this and come back to see how dumb I was lol, anyway, thank you alot for your work and for spending time to help, I really don't want to bother, see what I sent to RichMatheisen down there, see if you understand and maybe you could add it on RichMatheisen Script? but we're getting there

Answer 3

You have quite a problem to solve! This won't fix the problem of orphaned resource records but it might buy you some time. It will keep all singleton "A" records, and it will remove all but the MOST RECENT resource record type (currently set to "A") based on the timestamp. It ignores all records that are static (i.e. have no timestamp).

NOTE: I HAVE NOT TESTED THIS AT ALL.
I do have a "-WhatIf" on the Remove-DnsServerResourceRecord, but still use caution and TEST

$zonename = "your.dns.zone.name.goes.here"  
$recordtype = "A"  
$SpecialNames = "DomainDnsZones", "ForestDnsZones", "@"  
$RR = Get-DnsServerResourceRecord -ZoneName $zonename |  
                Where-Object {$_.RecordType -eq $recordtype -and $null -ne $_.TimeStamp -and $SpecialNames -notcontains $_.HostName} |  
                    Sort-Object -Property   @{Expression="HostName";Descending=$false},  
                                            @{Expression="TimeStamp";Descending=$true}  
  
$RR | Export-CSV C:\junk\$zonename.csv -NoTypeInformation   # just for recordkeeping!  
  
$currenthost = ""  
ForEach ($host in $RR) {  
    if ($currenthost -eq ""){  
        $currenthost = $host.HostName  
        continue  
    }  
    if ($host.HostName -eq $currenthost){   # duplicate  
        Remove-DnsServerResourceRecord -ZoneName $zonename -RRType $recordtype -Name $host.HostName -RecordData $host.recorddata.ipv4address.ipaddresstostring -WHATIF  
        continue  
    }  
    $currenthost = $host.HostName   # use this hostname to compare agains next hostname  
}

Jairon Junior 21 Reputation points

2022-01-14T11:00:07.643+00:00

Thank you, I'll ask for a colleague to test it and I'll give you a feedback about it, and what about the first script you sent me, the option to add a line there to show me what host is comunnicating with the IP isn't possible? Like the script is getting the hostnames on my txt file and showing me the ip of it, then you add a line doing the inverse operation, using the resulting ipv4 adress to show me the host that it's communicating, like I said i'm not trying to fix the problem, only avoid duplicated computers on the dns so I can move foward and let those for the last.

Answer 4

Where in the script would I add the Export-csv command to output the data of all the hostnames from the text file.

 Get-Content "C:TEMP\Servers and DCs.txt" |  
     ForEach-Object{  
         $result = [ordered]@{  
                     DNSName     = $_.Trim()  
                     HostName    = ""  
                     DNSIPv4     = ""  
                     Up          = ""  
                     TestedIPv4  = ""  
                     }  
         Try{  
             $entry = [System.Net.Dns]::GetHostEntry($_.Trim())  
             $result.HostName = $entry.HostName  
             $entry.AddressList |  
                 Where-Object {$_.AddressFamily -eq 'InterNetwork'} |  
                     ForEach-Object{  
                         $result.DNSIPv4 = $_.IPAddressToString  
                         [array]$x = Test-Connection -Delay 15 -ComputerName $result.DNSName -Count 1 -ErrorAction SilentlyContinue  
                         if ($x){  
                             $result.Up = "Yes"  
                             $result.TestedIPv4 = $x[0].IPV4Address  
                         }  
                         else{  
                             $result.Up = "No"  
                             $result.TestedIPv4 = "N/A"  
                         }  
                     }  
         }  
         Catch{  
             $result.HostName = "Host Unknown"  
             $result.Up = "Unknown"  
             $result.TestedIPv4 = "N/A"   
         }  
         [PSCustomObject]$result | Export-Csv -Path "C:\Temp\Servers&DC_DNS_Results.csv" -NoTypeInformation  
     }

Answer 5

Here's the problem: When you "ping" by IP address, the name of the host is retrieved from DNS by asking the server for the PTR record(s). In other words, it does a "reverse lookup", like getting a person's name by looking up their telephone number. So what happens if there are not only multiple "A" records for the host name (with different IP addresses), but also multiple "PTR" records for the IP address (with different host names)?

I don't know that your DNS lookups are deterministic. Can you rely on getting the answers to every query in the same order if there are multiple records that satisfy the query?

Right now I don't think you can rely on getting the answers you need from DNS, at least not without a lot more scripting.

However, you can try getting the name of the machine that's using an IP address right from the horse's mouth, so to speak, by asking the IP address's owner.

See if this helps:

Get-Content ".\ip4.txt" |
    ForEach-Object {
        $result = [ordered]@{
            DNSName           = $_.Trim()
            HostName          = ""
            DNSIPv4           = ""
            Up                = ""
            TestedIPv4        = ""
            AnsweringHostName = ""
            HostNamesMatch    = ""
        }
        Try {
            $entry = [System.Net.Dns]::GetHostEntry($_.Trim())
            $result.HostName = $entry.HostName
            $entry.AddressList |
                Where-Object { $_.AddressFamily -eq 'InterNetwork' } |
                    ForEach-Object {
                        $result.DNSIPv4 = $_.IPAddressToString
                        $result.AnsweringHostName = (Get-CimInstance -ClassName Win32_ComputerSystem -ComputerName $_.IPAddressToString).Name
                        $result.HostNamesMatch = $false
                        if ($result.AnsweringHostName -eq $result.HostName) {
                            $result.HostNamesMatch = $true
                        }
                        [array]$x = Test-Connection -Delay 15 -ComputerName $result.DNSName -Count 1 -ErrorAction SilentlyContinue
                        if ($x) {
                            $result.Up = "Yes"
                            $result.TestedIPv4 = $x[0].IPV4Address
                        }
                        else {
                            $result.Up = "No"
                            $result.TestedIPv4 = "N/A"
                        }
                    }
        }
        Catch {
            $result.HostName = "Host Unknown"
            $result.Up = "Unknown"
            $result.TestedIPv4 = "N/A"
        }
        [PSCustomObject]$result
    }

Jairon Junior 21 Reputation points

2022-01-17T11:25:18.337+00:00

It's giving me an error, and in all the hosts it results as false, some unknown, but that's ok, the first one you sent me was pretty good, I'll try to work with that and manually test if the ip and host match, thank you so much, really sorry for abusing of your kindness, have a wonderful week!!

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Script to ping multiple hosts and return if the IP corresponds to the correct host

4 additional answers

Your answer