On Mar 10, 7:18*pm, Rich <R...@discussions.microsoft.com> wrote:
> Hello Everyone,
>
> We're trying to troublshooot message delivery probems within our BizTalk
> 2006 R2 environment. *we are able to duplicate the problem in our QA
> environment. *We are getting a lot of the following errors:
>
> Event Type: * * Warning
> Event Source: * BizTalk Server 2006
> Event Category: (1)
> Event ID: * * * 5743
> Date: * * * * * 2/10/2009
> Time: * * * * * 1:36:35 PM
> User: * * * * * N/A
> Computer: * * * ECCAS774
> Description:
> The adapter failed to transmit message going to send port
> "WWWWW.XXXXX.YYYYY.prod" with URL
> "http://111.222.333.444:996/QQQQQQQ/BTSHTTPReceive.dll". It will be
> retransmitted after the retry interval specified for this Send Port.
> Details:"Unable to read data from the transport connection: The connection
> was closed.".
>
> We took a network capture and have tons of packets with bad checksums. *Not
> sure what this means yet, but network team is looking into it.
>
> We want to know what server is triggering the closing of the connection. *
>
> 2 questions:
>
> 1. *What do the following TCP flags mean:
> * * *ACK * * * * * *FIN * * * * * * SYN ** * * * PSH * * * * *Reset
>
> 2. *What would the flags be within the packet that signals a connectionto
> be closed?
>
> TIA,
> Rich
There are six ‘control bits’ defined in TCP, one or more of which is
defined in each packet. The control bits are ‘SYN’, ‘ACK’, ‘PSH’,
‘URG’, ‘RST’, and ‘FIN’. TCP uses these bits to define the purpose and
contents of a packet.
SYN bit is used in establishing a TCP connection to synchronize the
sequence numbers between both endpoints.
ACK bit is used to acknowledge the remote host’s sequence numbers,
declaring that the information in the acknowledgment field is valid.
PSH flag is set on the sending side, and tells the TCP stack to flush
all buffers and send any outstanding data up to and including the data
that had the PSH flag set. When the receiving TCP sees the PSH flag,
it too must flush its buffers and pass the information up to the
application.
URG bit indicates that the urgent pointer field has a valid pointer to
data that should be treated urgently and be transmitted before non-
urgent data.
Reset or RST is used to reset the connection. If a station involved in
a TCP session notices that it is not receiving acknowledgements for
anything it sends, the connection is now unsynchronized, and the
station should send a reset. This is a half-open connection where only
one side is involved in the TCP session. This cannot work by
definition of the protocol.
FIN bit is used to indicate that the client will send no more data
(but will continue to listen for data).
HTH
Alister
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