Test-Connection Performance Better with HostName

I just did a Wireshark trace while running Test-Connection with and without the Quiet switch parameter, supplying an IPv4 address for the Computername parameter.

When the Quiet switch is omitted, PowerShell seems to send not 1, but 6 NetBIOS Name Queries to the target machine, after which it returns the formatted output.

If I assign the output from Test-Connection, it returns right away, but as soon as I pipe it to Format-Table, it hangs and sends the NBSTAT queries again

The root cause is actually not the Test-Connection cmdlet itself, but the formatted output. One of the properties (IPV4Address) is a ScriptProperty and has the following definition:

PS C:\> $ping = Test-Connection -ComputerName 10.0.0.101 -Count 1PS C:\> Get-Member -InputObject $ping -Name IPV4Address | Select-Object -ExpandProperty DefinitionSystem.Object IPV4Address {get=$iphost = [System.Net.Dns]::GetHostEntry($this.address)                    $iphost.AddressList | ?{ $_.AddressFamily -eq [System.Net.Sockets.AddressFamily]::InterNetwork } | select -first 1;}

So, when the output shown, [System.Net.Dns]::GetHostEntry(10.0.0.101) is called to calculate IPV4Address - this is what causes the waiting time

If you don't care about the moot resolution of the IP address, use Select-Object to prevent the calculation and output of IPV4Address:

Test-Connection -ComputerName 10.0.0.101 -Count 1 | Select Address,StatusCode