Question about UdpClient?

[Emilio]

Question about UdpClient sample

' This constructor arbitrarily assigns the local port number.
Dim udpClient As New UdpClient()
Try
udpClient.Conne ct("www.contoso .com", 11000)

' Sends a message to the host to which you have connected.
Dim sendBytes As [Byte]() = Encoding.ASCII. GetBytes("Is anybody there?")

udpClient.Send( sendBytes, sendBytes.Lengt h)

' Sends message to a different host using optional hostname and port
parameters.
Dim udpClientB As New UdpClient()
udpClientB.Send (sendBytes, sendBytes.Lengt h, "AlternateHostM achineName",
11000)

'Blocks until a message returns on this socket from a remote host.
Dim RemoteIpEndPoin t As New IPEndPoint(IPAd dress.Any, 0)

' Blocks until a message returns on this socket from a remote host.
Dim receiveBytes As [Byte]() = udpClient.Recei ve(RemoteIpEndP oint)
Dim returnData As String = Encoding.ASCII. GetString(recei veBytes)
I was wondering what is the reason that when we need to receive
a message from a remote host we do IPAddress.Any,0
i.e why do we wait at port 0 rather than 11000, which is where
we sent to?

[Philip Rieck]

Your RemoteIpEndPoin t (with IPAddress.Any, port 0) is used only as a byref
parameter - that is, it is filled in with the actual IPAddress and port that
the data came from. So you're not listening on port 0. That's just a value
you're passing to a constructor because UdpClient.Recei ve takes a
constructed IPEndPoint - it's not actually used. If you want to limit the
host that you can accept UDP traffic from, specify that in the Connect
method (which you seem to havedone)
"Emilio" <[void]> wrote in message
news:uf******** ******@TK2MSFTN GP09.phx.gbl...

Question about UdpClient sample

' This constructor arbitrarily assigns the local port number.
Dim udpClient As New UdpClient()
Try
udpClient.Conne ct("www.contoso .com", 11000)

' Sends a message to the host to which you have connected.
Dim sendBytes As [Byte]() = Encoding.ASCII. GetBytes("Is anybody there?")

udpClient.Send( sendBytes, sendBytes.Lengt h)

' Sends message to a different host using optional hostname and port
parameters.
Dim udpClientB As New UdpClient()
udpClientB.Send (sendBytes, sendBytes.Lengt h, "AlternateHostM achineName",
11000)

'Blocks until a message returns on this socket from a remote host.
Dim RemoteIpEndPoin t As New IPEndPoint(IPAd dress.Any, 0)

' Blocks until a message returns on this socket from a remote host.
Dim receiveBytes As [Byte]() = udpClient.Recei ve(RemoteIpEndP oint)
Dim returnData As String = Encoding.ASCII. GetString(recei veBytes)
I was wondering what is the reason that when we need to receive
a message from a remote host we do IPAddress.Any,0
i.e why do we wait at port 0 rather than 11000, which is where
we sent to?

[Plem]

Philip,

You're obviously getting this to work... I've tried everything to get this
sample to work but I never receive anything. Both pc-s are connected ok; ping
works both ways and a udp test program gets messages across both ways. When I
use the Send method I get messages across fine. Receive only gives me
trouble. I copied the example from HELP. It throws an exception telling me I
'm feeding it an invalid argument...

It all lookde straight forward but I'm getting desparate

Peter

"Philip Rieck" wrote:

Your RemoteIpEndPoin t (with IPAddress.Any, port 0) is used only as a byref
parameter - that is, it is filled in with the actual IPAddress and port that
the data came from. So you're not listening on port 0. That's just a value
you're passing to a constructor because UdpClient.Recei ve takes a
constructed IPEndPoint - it's not actually used. If you want to limit the
host that you can accept UDP traffic from, specify that in the Connect
method (which you seem to havedone)
"Emilio" <[void]> wrote in message
news:uf******** ******@TK2MSFTN GP09.phx.gbl...

Question about UdpClient sample

' This constructor arbitrarily assigns the local port number.
Dim udpClient As New UdpClient()
Try
udpClient.Conne ct("www.contoso .com", 11000)

' Sends a message to the host to which you have connected.
Dim sendBytes As [Byte]() = Encoding.ASCII. GetBytes("Is anybody there?")

udpClient.Send( sendBytes, sendBytes.Lengt h)

' Sends message to a different host using optional hostname and port
parameters.
Dim udpClientB As New UdpClient()
udpClientB.Send (sendBytes, sendBytes.Lengt h, "AlternateHostM achineName",
11000)

'Blocks until a message returns on this socket from a remote host.
Dim RemoteIpEndPoin t As New IPEndPoint(IPAd dress.Any, 0)

' Blocks until a message returns on this socket from a remote host.
Dim receiveBytes As [Byte]() = udpClient.Recei ve(RemoteIpEndP oint)
Dim returnData As String = Encoding.ASCII. GetString(recei veBytes)
I was wondering what is the reason that when we need to receive
a message from a remote host we do IPAddress.Any,0
i.e why do we wait at port 0 rather than 11000, which is where
we sent to?