Ping takes way too long

[Confuzzled]

I'm trying to find all devices on the local LAN segment. I figure if I ping all 256 addresses on the local segment, then this should be a fair indicator of devices that are currently active on it.

I loop through all addresses and ping them. Traditionally they should respond with a microsecond or two, and ping times should be brief.

I'm finding that each ping is taking about a third of a second, making a 256 pass loop take a few minutes.

Sample (working) code extracted from a larger program I have written is attached. I've taken to putting up a Splashbox to show progress so users don't think that the process has stopped or frozen. Even with feedback removed, it is still taking way too long.

expandcollapse popup

;GetIP.inc
; get IP addresses

;Note: should compare the public IP address with the others extracted and check for following:
; 1 - Are they the same - if not then are behind a router of some kind
; 2 - Private IP range: 10.0.0.0-10.255.255.255 or 172.16.0.0 - 172.31.255.255 or 192.168.0.0 - 192.168.255.255
; 3 - Automatic Private addressing 169.254.0.0 169.254.255.255
; If any of the above are valid, further information should be given regarding configuration of firewalls and routers

;Ping rest of LAN segment if local address found to search for other devices present - should identify any shared Internet connections

Dim $IP_Add ;Temporary IP Address
Dim $IP_Add_Masked[3] ; Variable to split IP address into octets
$bd_Behind_Router = "NO" ; Set to known value
$bd_Out = $bd_Out & "Internet "

; get public IP address from site [url="http://www.dslreports.com/whois"]http://www.dslreports.com/whois[/url]
$bd_Current_IP_Address_Full = GetIP()
$bd_Current_IP_Address_Masked = CheckIPAddress($bd_Current_IP_Address_Full)
;Get the IP addresses of the first four network adapters on the system
If @IPAddress1 = $bd_Current_IP_Address_Full Then
 $bd_Current_IP_Adapter_1 = $bd_Current_IP_Address_Full
Else
 $bd_Current_IP_Adapter_1 = CheckIPAddress(@IPAddress1)
 $bd_Behind_Router = "YES"
EndIf
$bd_Current_IP_Adapter_2 = CheckIPAddress(@IPAddress2)
$bd_Current_IP_Adapter_3 = CheckIPAddress(@IPAddress3)
$bd_Current_IP_Adapter_4 = CheckIPAddress(@IPAddress4)

If $bd_Diag_Mode = 1 Then
 MsgBox(0, "IP Addresses", "Your public IP Address is: " & @TAB & $bd_Current_IP_Address_Full & @CRLF & _
 "Masked (Privacy): " & @TAB & @TAB & $bd_Current_IP_Address_Masked & @CRLF & @CRLF & _
 "Network adapter 1 address: " & @TAB & $bd_Current_IP_Adapter_1 & ", " & @CRLF & _
 "Network adapter 2 address: " & @TAB & $bd_Current_IP_Adapter_2 & ", " & @CRLF & _
 "Network adapter 3 address: " & @TAB & $bd_Current_IP_Adapter_3 & ", " & @CRLF & _
 "Network adapter 4 address: " & @TAB & $bd_Current_IP_Adapter_4 & ", " & @CRLF & @CRLF & _
 "Behind NAT Firewall/Router? "  & @TAB & $bd_Behind_Router)
EndIf

If $bd_Behind_Router = "YES" Then
 $bd_Out = $bd_Out & " You are behind a NAT firewall and/or router." & @CRLF
EndIf

$bd_Out = $bd_Out & @CRLF
ClipPut ($bd_Out)

Func CheckIPAddress($IP_Add)
Select
 Case $IP_Add = "NOT CONNECTED"
  Return $IP_Add
    Case $IP_Add = "0.0.0.0"
        Return $IP_Add
    Case StringLeft($IP_Add, 3) = "10."
  $bd_Out = $bd_Out & "Local IP Address " & $IP_Add & " "
        $bd_Behind_Router = "YES"
  PingCheck($IP_Add) ;Check by pinging all addresses in local range to see if other devices on LAN are reachable
  Return $IP_Add
 Case StringLeft($IP_Add, 8) = "192.168."
  $bd_Out = $bd_Out & "Local IP Address " & $IP_Add & " "
  $bd_Behind_Router = "YES"
  PingCheck($IP_Add) ;Check by pinging all addresses in local range to see if other devices on LAN are reachable
  Return $IP_Add
 Case StringLeft($IP_Add, 8) = "169.254."
  $bd_Out = $bd_Out & "Automatic Local IP Address " & $IP_Add & " "
  $bd_Behind_Router = "YES"
  PingCheck($IP_Add) ;Check by pinging all addresses in local range to see if other devices on LAN are reachable
  Return $IP_Add
 Case (StringLeft($IP_Add, 4) = "172.") AND (Number(StringMid ($IP_Add, 5,3)) > 15) AND (Number(StringMid ($IP_Add, 5,3)) < 32)
  $bd_Out = $bd_Out & "Local IP Address " & $IP_Add & " "
  $bd_Behind_Router = "YES"
  PingCheck($IP_Add) ;Check by pinging all addresses in local range to see if other devices on LAN are reachable
  Return $IP_Add
 Case Else
        ; This is where we mask off the last two octets
  ; Concatenate the first and second only and mask the third and fourth octet
  $IP_Add_Masked = StringSplit($IP_Add,".")
  ; Check that StringSplit actually found an IP octet
  If $IP_Add_Masked[0] > 2 Then
   $IP_Add = $IP_Add_Masked[1] & "." & $IP_Add_Masked[2] & ".xxx.xxx"
  EndIf
  $bd_Out = $bd_Out & "IP Address " & $IP_Add & " "
  Return $IP_Add
 EndSelect
EndFunc ; <<= CheckIPAddress

Func GetIP()
 ; GetIP
 ; get public IP address from site [url="http://www.dslreports.com/whois"]http://www.dslreports.com/whois[/url]
 Local $ip
 If InetGet("[url="http://www.dslreports.com/whois"]http://www.dslreports.com/whois[/url]", @TempDir & "\~ip.tmp",1,0) Then
  $ip = FileRead(@TempDir & "\~ip.tmp")
  FileDelete(@TempDir & "\~ip.tmp")
  $ip = StringTrimLeft($ip, StringInStr($ip, "The IP that just fetched this page is<br>") + 40)
  $ip = StringLeft($ip, StringInStr($ip, "<br>") - 1)      
  Return $ip
 Else
  SetError(1)
  $ip = "NOT CONNECTED"
  Return $ip
 EndIf
EndFunc ; <<= GetIP

Func PingCheck($IP_Add)
 ;Ping all addresses in local network segment (count = 256)
 Local $Count ; Iteration counter
 Local $IP_Address ; IP Address being pinged
 Local $IP_Address_Masked[3] ; Variable to split IP address into octets
 Local $IP_Address_3  ;First three octets of $IP_Address_Masked
 Local $IP_Range ; Range to be tested
 $IP_Address_Masked = StringSplit($IP_Add,".") ; Split it up into four octets
 $IP_Address_3 = $IP_Address_Masked[1] & "." & $IP_Address_Masked[2] & "." & $IP_Address_Masked[3] & "." ; Build first three octets
 $IP_Range = "Range " & $IP_Address_3 & "0 - " & $IP_Address_3 & "255"
 ConsoleWrite("IP Address segment being pinged is " & $IP_Add & @CRLF)
 SplashTextOn("   Checking local network connections", @LF & "Checking IP address" & @LF & $IP_Add,300,100)
 
 For $Count = 0 to 255 Step 1 ;Do for all 256 addresses in fourth octet
  $IP_Address = $IP_Address_3 & $Count ; Build IP address to ping
  If Ping($IP_Address, 5) > 0 Then ; only report successful pings
   If $IP_Address <> $IP_Add Then ; skip for actual IP address - only do for all others in segment
    $bd_Out = $bd_Out & " Another device found at " & $IP_Address
   EndIf
  EndIf
 ControlSetText("   Checking local network connections", "", "Static1", @LF & "Looking for IP address " & $IP_Address & @LF & @LF & $IP_Range)
 TrayTip("Checking local connections","        IP address: " & $IP_Address , 10, 17)
 Next
TrayTip ("", "", 0,0) ; Turn off traytip
SplashOff() ; Turn off splash text
EndFunc ; <<= PingCheck

Is there some alternate way of doing this that somebody can recommend?

[lod3n]

Before you ping, why not ask your name server if it's heard of the IP in question? Like so:

#include <Constants.au3> ; required for StderrRead

; include this little function I wrote...
Func NsKnowsIp($ip)
    $foo = Run("nslookup "&$ip, @SystemDir, @SW_HIDE, $STDERR_CHILD)
    $output = ""
    While 1
        $output &= StderrRead($foo)
        If @error Then ExitLoop
    Wend
    if stringinstr($output,"can't find " & $ip) Then
        return false
    Else
        return True
    EndIf
endfunc


; example usage

if NsKnowsIp("127.0.0.1") then
    msgbox(0,"","127.0.0.1 is known")
Else
    msgbox(0,"","127.0.0.1 is unknown")
EndIf

if NsKnowsIp("127.0.0.2") then
    msgbox(0,"","127.0.0.2 is known")
Else
    msgbox(0,"","127.0.0.2 is unknown")
EndIf

[CoePSX]

I did this a while ago on a local netsend messenger for my home network

This is the function to check the machine status.

Func CheckMachineStatus($sMachine)
    Local $pPing = Run("ping -w 50 -n 1 -l 8 " & $sMachine, "", @SW_HIDE, $STDOUT_CHILD)
    Local $pPingTimer = TimerInit()
    Local $pFinalRead = ""
    While ProcessExists($pPing) And TimerDiff($pPingTimer) < 2000
        If Mod(Floor(TimerDiff($pPingTimer)), 50) = 0 Then
            Switch GUICtrlRead($Status)
                Case "|"
                    GUICtrlSetData($Status, "/")
                Case "\"
                    GUICtrlSetData($Status, "|")
                Case "--"
                    GUICtrlSetData($Status, "\")
                Case "/"
                    GUICtrlSetData($Status, "--")
            EndSwitch
        EndIf
        $pPingRead = StdoutRead($pPing, -1, True)
        If $pPingRead <> "" Then
            $pFinalRead &= $pPingRead
        EndIf
    WEnd
    TimerStop($pPingTimer)
    If StringLen($pFinalRead) > 200 Then $pFinalRead = StringRight($pFinalRead, 200)
    If IsArray(StringRegExp($pFinalRead, "(\d+)%", 1)) Then
        Return 1
    Else
        Return 0
    EndIf
EndFunc

OBS: the -n 1 in the ping line means "just ping it once", when the default is 4, that's why it takes too

long. This one is faster.

Edited August 17, 2006 by CoePSX

[Confuzzled]

Thanks for the input from both of you. I'll investigate the DOS commands further.