tcp broadcast address listen

[ghetek]

I was looking at the following thread,

http://www.autoitscript.com/forum/index.ph...opic=29772&

and noticed that the connection was made to a broacast address.

I am trying to make a program that sends a few packets of info to the broadcast and those packets are picked up by all computers on the network that are currently listening. i tried changing the tcp chat example in the help file to the broadcast address on both the client and the server and i just get some error. is there an easy way to do communication using the broadcast?

[martin]

I was looking at the following thread,

http://www.autoitscript.com/forum/index.ph...opic=29772&

and noticed that the connection was made to a broacast address.

I am trying to make a program that sends a few packets of info to the broadcast and those packets are picked up by all computers on the network that are currently listening. i tried changing the tcp chat example in the help file to the broadcast address on both the client and the server and i just get some error. is there an easy way to do communication using the broadcast?

I think that to broadcast you need to use UDP. UDP sends a datagram (like sending a letter) which can be addressed to one ip or may (like junkmail). TCP establishes a connection between two ip address, like making a phone call. You cannot broadcast beyond a local area network because routers block broadcast packets. A chat program should work fine using UDP on a local network. If you want to use TCP for some reason then you could broadcat a UDP message, examine the replies and decide which one to communicate with using TCP.

[ghetek]

I think that to broadcast you need to use UDP. UDP sends a datagram (like sending a letter) which can be addressed to one ip or may (like junkmail). TCP establishes a connection between two ip address, like making a phone call. You cannot broadcast beyond a local area network because routers block broadcast packets. A chat program should work fine using UDP on a local network. If you want to use TCP for some reason then you could broadcat a UDP message, examine the replies and decide which one to communicate with using TCP.

ok i will try to change the chat program to udp for now and see if i can get this working, thanks martin!

[ghetek]

I still cant get this working

This is the broadcast code

$IPAddress = "192.168.1.255"; This is the broadcast address !


UDPStartUp()

$connection = UDPOpen($IPAddress, 65532)
$res = UDPSend($connection,"superdata")
MsgBox(0, "", $res)

UDPCloseSocket($connection)
UDPShutdown()

This is the recieve code

UDPStartup()
$socket = UDPBind("192.168.1.255", 65532)
If @error <> 0 Then Exit

While 1
    $data = UDPRecv($socket, 50)
    If $data <> "" Then
        MsgBox(0, "UDP DATA", $data, 1)
    EndIf
    sleep(100)
WEnd

Func OnAutoItExit()
    UDPCloseSocket($socket)
    UDPShutdown()
EndFunc

[nitekram]

I still cant get this working

This is the broadcast code

$IPAddress = "192.168.1.255"; This is the broadcast address !
UDPStartUp()

$connection = UDPOpen($IPAddress, 65532)
$res = UDPSend($connection,"superdata")
MsgBox(0, "", $res)

UDPCloseSocket($connection)
UDPShutdown()

This is the recieve code

UDPStartup()
$socket = UDPBind("192.168.1.255", 65532)
If @error <> 0 Then Exit

While 1
    $data = UDPRecv($socket, 50)
    If $data <> "" Then
        MsgBox(0, "UDP DATA", $data, 1)
    EndIf
    sleep(100)
WEnd

Func OnAutoItExit()
    UDPCloseSocket($socket)
    UDPShutdown()
EndFunc

Have you tested the server to see if it has the port open - when I ran your code on the server it closed, but when I changed the IP to $socket = UDPBind("127.0.0.1", 65532) it stayed open and I checked for the port and it was opened.

[ghetek]

Have you tested the server to see if it has the port open - when I ran your code on the server it closed, but when I changed the IP to $socket = UDPBind("127.0.0.1", 65532) it stayed open and I checked for the port and it was opened.

The only issue that i see is that if i run the udpbind to 127.0.0.1 then i will not recieve broadcast packets but only local ones. how can i make the receive work for all braodcast packets on the network? in the end i will have the recieve (server) running on 10 computers and the broadcaster (the client) running on only one system.

[ghetek]

when both are running as 127.0.0.1, it works great but as i said i am not getting anythign when the server is set to 127.0.0.1 and the client sends to the broadcast.

[nfwu]

Is your LAN range 192.168.1.0 with an IP mask of 255.255.0.0?

Maybe you are using the wrong IP address.

What is the LAN IP address of one of your computers and what is the IP mask?

#)

[nitekram]

Try this - make sure you notice that there is server code and client code

expandcollapse popup

#cs
;server

;;This is the UDP Server
;;Start this first

; Start The UDP Services
;==============================================
UDPStartup()
If @error <> 0 Then
    MsgBox(0, "UDP Startup ERROR", @error, 1)
    Exit
EndIf

; Bind to a SOCKET
;==============================================
$socket = UDPBind(@IPAddress1, 65532)
If @error <> 0 Then
    MsgBox(0, "UDP BIND ERROR", @error, 1)
    Exit
EndIf

While 1
    $data = UDPRecv($socket, 50)
    If $data <> "" Then
        MsgBox(0, "Message:", $data)
    EndIf
    sleep(100)
WEnd

Func OnAutoItExit()
    UDPCloseSocket($socket)
    UDPShutdown()
EndFunc

#ce



;#cs
;client
    
;;This is the UDP Client
;;Start the server first

; Start The UDP Services
;==============================================
UDPStartup()
If @error <> 0 Then
    MsgBox(0, "UDP Startup ERROR", @error, 1)
    Exit
EndIf

; Open a "SOCKET"
;==============================================
$socket = UDPOpen("192.168.0.255", 65532)
$text = ''
For $i = 0 to UBound($socket) -1
$text = $text & @LF & $socket[$i] & @LF
Next
MsgBox(0,"UDPOpen",$text)
If @error <> 0 Then
    MsgBox(0, "UDP Open ERROR", @error, 1)
    Exit
EndIf

;#cs
$n=0
While 1
    Sleep(2000)
    $n = $n + 1
    $status = UDPSend($socket, "Message # " & $n)
    ;MsgBox(0,'$status',$status)
    If $status = 0 then 
        MsgBox(0, "ERROR", "Error while sending UDP message: " & @error)
        Exit
    EndIf
WEnd
;#ce

;UDPSend($socket, "your message")

Func OnAutoItExit()
    UDPCloseSocket($socket)
    UDPShutdown()
EndFunc
    
;#ce

edit fixed code

Edited March 4, 2007 by nitekram