PowerShell/docs/list-dns-servers.md
2023-10-31 11:05:01 +01:00

66 lines
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Markdown

*list-dns-servers.ps1*
================
list-dns-servers.ps1
Parameters
----------
```powershell
[<CommonParameters>]
This script supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction,
WarningVariable, OutBuffer, PipelineVariable, and OutVariable.
```
Script Content
--------------
```powershell
<#
.SYNOPSIS
Lists DNS servers
.DESCRIPTION
This PowerShell script measures the latency of public and free DNS servers and lists it.
.EXAMPLE
PS> ./list-dns-servers.ps1
Provider IPv4 Latency
-------- ---- -------
AdGuard DNS (Cyprus) 94.140.14.14 / 94.140.15.15 222 / 205 ms
...
.LINK
https://github.com/fleschutz/PowerShell
.NOTES
Author: Markus Fleschutz | License: CC0
#>
function CheckDNSServer { param($Provider, $IPv4Pri, $IPv4Sec)
Write-Progress "Measuring latency of $Provider..."
$SW=[system.diagnostics.stopwatch]::startNew();$null=(nslookup fleschutz.de $IPv4Pri 2>$null);[int]$Lat1=$SW.Elapsed.TotalMilliseconds
$SW=[system.diagnostics.stopwatch]::startNew();$null=(nslookup fleschutz.de $IPv4Sec 2>$null);[int]$Lat2=$SW.Elapsed.TotalMilliseconds
New-Object PSObject -Property @{ Provider=$Provider; IPv4="$IPv4Pri / $IPv4Sec"; Latency="$Lat1 / $Lat2 ms" }
}
function List-DNS-Servers {
Write-Progress "Loading Data/public-dns-servers.csv..."
$Table = Import-CSV "$PSScriptRoot/../Data/public-dns-servers.csv"
foreach($Row in $Table) {
CheckDNSServer $Row.PROVIDER $Row.IPv4_PRI $Row.IPv4_SEC
}
Write-Progress -completed "."
}
try {
List-DNS-Servers | Format-Table -property @{e='Provider';width=50},@{e='IPv4';width=32},@{e='Latency';width=15}
exit 0 # success
} catch {
"⚠️ Error in line $($_.InvocationInfo.ScriptLineNumber): $($Error[0])"
exit 1
}
```
*(generated by convert-ps2md.ps1 using the comment-based help of list-dns-servers.ps1 as of 10/19/2023 08:11:39)*