69 lines
1.8 KiB
PowerShell
69 lines
1.8 KiB
PowerShell
|
<#
|
||
|
|
|
||
|
|
.SYNOPSIS
|
||
|
|
Sends ICMPv4 echo request packets to a given IPv4 address
|
||
|
|
with various payload sizes until the maximum transmission unit is found.
|
||
|
|
|
||
|
|
.DESCRIPTION
|
||
|
|
Inspired by the script of Charles_1.0 I created a function that uses
|
||
|
|
the .Net ping class to find the biggest transmission unit size.
|
||
|
|
It simple and fast.
|
||
|
|
Just open Powershell, run the script and type Find-MTU <ipaddress> to get the result.
|
||
|
|
|
||
|
|
.INPUTS
|
||
|
|
None
|
||
|
|
You cannot pipe input to this cmdlet.
|
||
|
|
|
||
|
|
.OUTPUTS
|
||
|
|
The function returns an integer that represents the MTU size.
|
||
|
|
|
||
|
|
.NOTES
|
||
|
|
Author: G.A.F.F. Jakobs
|
||
|
|
Version: 1.3
|
||
|
|
|
||
|
|
.EXAMPLE
|
||
|
|
Find-MTU 192.168.1.254
|
||
|
|
|
||
|
|
.LINK
|
||
|
|
http://gallery.technet.microsoft.com/Find-the-Biggest-MTU-size-ff1c6069
|
||
|
|
|
||
|
|
#>
|
||
|
|
|
||
|
|
[CmdletBinding(SupportsShouldProcess=$True,ConfirmImpact='Low')]
|
||
|
|
Param(
|
||
|
|
[parameter(Mandatory = $true, Position = 0)]
|
||
|
|
[System.Net.IPAddress]$IPaddress
|
||
|
|
)
|
||
|
|
|
||
|
|
$Ping = New-Object System.Net.NetworkInformation.Ping
|
||
|
|
$PingOptions = New-Object System.Net.NetworkInformation.PingOptions
|
||
|
|
$PingOptions.DontFragment = $true
|
||
|
|
|
||
|
|
[int]$Timeout = 1000
|
||
|
|
[int]$SmallMTU=1
|
||
|
|
[int]$LargeMTU=35840
|
||
|
|
|
||
|
|
[byte[]]$databuffer = ,0xAC * $LargeMTU
|
||
|
|
|
||
|
|
|
||
|
|
#action
|
||
|
|
|
||
|
|
While (-not ($SmallMTU -eq ($LargeMTU - 1))) {
|
||
|
|
[int]$xTest= ($LargeMTU - $SmallMTU) / 2 + $SmallMTU
|
||
|
|
|
||
|
|
$PingReply = $Ping.Send($IPaddress, $Timeout, $($DataBuffer[1..$xTest]), $PingOptions)
|
||
|
|
Write-Verbose "testing $($xTest + 28) byte transmission unit size"
|
||
|
|
if ($PingReply.Status -match "Success"){
|
||
|
|
$SmallMTU = $xTest
|
||
|
|
}
|
||
|
|
else{
|
||
|
|
$LargeMTU = $xTest
|
||
|
|
}
|
||
|
|
Start-Sleep -Milliseconds 50
|
||
|
|
}
|
||
|
|
|
||
|
|
If($SmallMTU -eq 1){
|
||
|
|
Write-Error "The IP address $IPaddress does not respond."
|
||
|
|
}else{
|
||
|
|
return $SmallMTU + 28 # add 28 bytes because 20 bytes are reserved for the IP header and 8 bytes must be allocated for the ICMP Echo Request header.
|
||
|
|
}
|