PowerShell - IP to HostName resolve from text list

Save as a named .ps1. This is the IP to host versus the latter, this one becomes invaluable if doing any traceroute items and need to list IP's out to resolve.

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# Get list from file, initialize empty array

$ListOfIPs=Get-content "c:\temp\IPs.txt"

$ResultList = @()

# roll through the list, resolving as we

# go with the .Net DNS resolver

foreach ($IP in $ListOfIPs)

{

# We don't want to see any errors as we go, right?

$ErrorActionPreference = "silentlycontinue"

$Result = $null

# status to user, just so they know that something

# is still happening, then pass the current IP

# to .Net for name resolution.

write-host "resolving $IP"

$result = [System.Net.Dns]::gethostentry($IP)

# Enter into the array, with the returned results.

If ($Result)

{

$ResultList += "$IP," + [string]$Result.HostName

}

Else

{

$ResultList += "$IP,unresolved"

}

}

# send it out to a file, and inform the user we are done

$ResultList | Out-File c:\temp\IPsresolved.txt

write-host "name resolution complete"

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