vb.net and sockets bug?

[buc]

Why does VB.NET UDP sockets send data on random ports?. If I set a simple
socket up to transmit a UDP packet on a port, look at the packet with a
sniffer, the actual packets source port and dest.port are diff. The packets
destination port is correct, but the packets source port it is actually sent
from is random. Why? How can I figure out the actual source port windows is
using, not what the vb.net socket is fake reporting?
Thanks BUC

[Henning Krause [MVP - Exchange]]

Hello,

have you bound your local socket to an explicit port?

Dim socket as Socket

socket = new Socket(...)

socket.Bind(new IPEndPoint(IPAd dress.Any), port_number)

Best regards,
Henning Krause

"buc" <bu******@hotma il.com_removewr ote in message
news:uB******** ******@TK2MSFTN GP06.phx.gbl...

Why does VB.NET UDP sockets send data on random ports?. If I set a simple
socket up to transmit a UDP packet on a port, look at the packet with a
sniffer, the actual packets source port and dest.port are diff. The
packets destination port is correct, but the packets source port it is
actually sent from is random. Why? How can I figure out the actual source
port windows is using, not what the vb.net socket is fake reporting?
Thanks BUC

[buc]

Yes, I bind to a port, for example 9001, and 9001 is placed into the packet
as the destination port, but the source send port is in the 2000 range. This
appears to be a bug, and is easily reproducable with only a few lines of
code. Even example code from the MSDN. I tried the same code on XP or 2003
server platform with the same results.
BUC

"buc" <bu******@hotma il.com_removewr ote in message
news:uB******** ******@TK2MSFTN GP06.phx.gbl...

Why does VB.NET UDP sockets send data on random ports?. If I set a simple
socket up to transmit a UDP packet on a port, look at the packet with a
sniffer, the actual packets source port and dest.port are diff. The
packets destination port is correct, but the packets source port it is
actually sent from is random. Why? How can I figure out the actual source
port windows is using, not what the vb.net socket is fake reporting?
Thanks BUC

[Henning Krause [MVP - Exchange]]

Hello,

please post your code here.

Best regards,
Henning Krause

"buc" <bu******@hotma il.com_removewr ote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

Yes, I bind to a port, for example 9001, and 9001 is placed into the
packet as the destination port, but the source send port is in the 2000
range. This appears to be a bug, and is easily reproducable with only a
few lines of code. Even example code from the MSDN. I tried the same code
on XP or 2003 server platform with the same results.
BUC

"buc" <bu******@hotma il.com_removewr ote in message
news:uB******** ******@TK2MSFTN GP06.phx.gbl...

>Why does VB.NET UDP sockets send data on random ports?. If I set a
simple socket up to transmit a UDP packet on a port, look at the packet
with a sniffer, the actual packets source port and dest.port are diff.
The packets destination port is correct, but the packets source port it
is actually sent from is random. Why? How can I figure out the actual
source port windows is using, not what the vb.net socket is fake
reporting?
Thanks BUC

[bucrepus]

Dim UpdateIP As IPAddress
Dim packet(2) As Byte
Dim txSocket As Socket = New Socket(AddressF amily.InterNetw ork,
SocketType.Dgra m, ProtocolType.Ud p)
'load some data of some sort
packet(0) = 1 : packet(0) = 1
UpdateIP = IPAddress.Parse ("192.168.0.100 ")
txSocket = New Socket(AddressF amily.InterNetw ork, SocketType.Dgra m,
ProtocolType.Ud p)
Dim txPLCEP As New IPEndPoint(Upda teIP, 9001)
txSocket.SendTo (packet, txPLCEP)
txSocket.Close( )
txSocket = Nothing

'packet is transmitted to 192.168.0.100 with a source dest port of 9001 and
a source send port of 2039. Depending on the machine I test this code
on the source send port randomly changes around the 2000 range. verified
with 2 diff packet sniffers including W2k3 server net monitor.

Thanks..
N\BUC


"buc" <bu******@hotma il.com_removewr ote in message
news:uB******** ******@TK2MSFTN GP06.phx.gbl...

Why does VB.NET UDP sockets send data on random ports?. If I set a simple
socket up to transmit a UDP packet on a port, look at the packet with a
sniffer, the actual packets source port and dest.port are diff. The
packets destination port is correct, but the packets source port it is
actually sent from is random. Why? How can I figure out the actual source
port windows is using, not what the vb.net socket is fake reporting?
Thanks BUC

[Henning Krause [MVP - Exchange]]

Hello,

1. Why are you creating the sockets two times?

2. Add a txSocket.Bind(n ew IPEndPoint(IPAd dress.Any), 1234)

This will bind the socket to the local port 1234, and should solve your
issue.

Best regards,
Henning Krause

"bucrepus" <bu******@hotma il.com_removewr ote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

Dim UpdateIP As IPAddress
Dim packet(2) As Byte
Dim txSocket As Socket = New Socket(AddressF amily.InterNetw ork,
SocketType.Dgra m, ProtocolType.Ud p)
'load some data of some sort
packet(0) = 1 : packet(0) = 1
UpdateIP = IPAddress.Parse ("192.168.0.100 ")
txSocket = New Socket(AddressF amily.InterNetw ork, SocketType.Dgra m,
ProtocolType.Ud p)
Dim txPLCEP As New IPEndPoint(Upda teIP, 9001)
txSocket.SendTo (packet, txPLCEP)
txSocket.Close( )
txSocket = Nothing

'packet is transmitted to 192.168.0.100 with a source dest port of 9001
and a source send port of 2039. Depending on the machine I test this code
on the source send port randomly changes around the 2000 range. verified
with 2 diff packet sniffers including W2k3 server net monitor.

Thanks..
N\BUC


"buc" <bu******@hotma il.com_removewr ote in message
news:uB******** ******@TK2MSFTN GP06.phx.gbl...

>Why does VB.NET UDP sockets send data on random ports?. If I set a
simple socket up to transmit a UDP packet on a port, look at the packet
with a sniffer, the actual packets source port and dest.port are diff.
The packets destination port is correct, but the packets source port it
is actually sent from is random. Why? How can I figure out the actual
source port windows is using, not what the vb.net socket is fake
reporting?
Thanks BUC

[bucrepus]

Sorry about the double creation. Changing the bind to 1234 does bind PART of
the local port 1234. If I issue a sendto as in my code Sendto(...,1234 ), the
actual setup of the packet from vb.net shows a send source port of 2011 and
a send dest port of 1234. which is only halfway correct, as verified by
windows network monitor. This is def. a BUG.
I am trying to do something simple. I send to a remote machine(nonwind ows)
with a simple UDP packet. I used the code to send 2 bytes of data on port
9001. The remote receives the data but transmits a packet back to me on the
REAL send source port the VB program sent it on which is NOT 9001, it looks
like a windows assigned port. In fact the MSDN says it if you dont assign
the SEND SOURCE PORT for the packet , it will assign a port in the
2000-65535 range. VB is only setting the dest port part of the packet, not
the source send port part of it. I you actually fired the code off and
lookup at it with a sniffer, this happens every time. I am very
frustrated.Sinc e windows is assigning a random port, I cant use the bind to
figure out what port to listen on. Using a sniffer it is easy to see this
bug, using MSDN code or mine, Ive tried several examples from MSDN with same
results.
Any more ideas?
Thanks BUC

"Henning Krause [MVP - Exchange]" <ne************ ***@this.infini tec.de>
wrote in message news:u1******** ******@TK2MSFTN GP05.phx.gbl...

Hello,

1. Why are you creating the sockets two times?

2. Add a txSocket.Bind(n ew IPEndPoint(IPAd dress.Any), 1234)

This will bind the socket to the local port 1234, and should solve your
issue.

Best regards,
Henning Krause

"bucrepus" <bu******@hotma il.com_removewr ote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

>Dim UpdateIP As IPAddress
Dim packet(2) As Byte
Dim txSocket As Socket = New Socket(AddressF amily.InterNetw ork,
SocketType.Dgr am, ProtocolType.Ud p)
'load some data of some sort
packet(0) = 1 : packet(0) = 1
UpdateIP = IPAddress.Parse ("192.168.0.100 ")
txSocket = New Socket(AddressF amily.InterNetw ork, SocketType.Dgra m,
ProtocolType.U dp)
Dim txPLCEP As New IPEndPoint(Upda teIP, 9001)
txSocket.SendT o(packet, txPLCEP)
txSocket.Close ()
txSocket = Nothing

'packet is transmitted to 192.168.0.100 with a source dest port of 9001
and a source send port of 2039. Depending on the machine I test this code
on the source send port randomly changes around the 2000 range. verified
with 2 diff packet sniffers including W2k3 server net monitor.

Thanks..
N\BUC


"buc" <bu******@hotma il.com_removewr ote in message
news:uB******* *******@TK2MSFT NGP06.phx.gbl.. .

>>Why does VB.NET UDP sockets send data on random ports?. If I set a
simple socket up to transmit a UDP packet on a port, look at the packet
with a sniffer, the actual packets source port and dest.port are diff.
The packets destination port is correct, but the packets source port it
is actually sent from is random. Why? How can I figure out the actual
source port windows is using, not what the vb.net socket is fake
reporting?
Thanks BUC