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SMTP TCP/IP connection drops




I have been using labview SMTP library for TCP/IP connections to have multiple connection architecture all clients

(two) and server (one) are connected to unmanaged switch through 1 Gbit (Ethernet Switch). What happens now is


1-      If only one client is connected (through Switch) to server then if I unplug the clients or Servers Ethernet cable

        the client goes down and after that the server drops the client  connection. (fine Ok) But


2-      If I have connected two clients (through Switch) to server and now if I unplug any one of clients Network cable 

        the 2nd client also goes down ,stops running and server  drops his connection as well even though his network

        cable is not unplugged also it has not been stopped by client application.


anyone who came across this situation and how to deal with





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Message 1 of 6

Hello madd,


Are you sure of the sequence that you mentioned in your second point (where client 1 gets unplugged >> client 1 goes down >> client 2 goes down >> server goes down). When I think about this issue, I would expect that when the first client is unplugged the server throws an error and no longer functions correctly. Once the server goes down, this would casue the second client to error our as well. Would it be possible to implement an error handler on the client side that will discard the error caused when a client loses connection and then reconnect with the existing clients?


I would appreciate either a snippet of the code that you are using, or the entire vi in order to better help you diagnose this issue.





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Message 2 of 6




 Thanks for ur reply


 i am very much sure about sequence cuz if i unplugg client 1 i have no error that stops the server vi it just drops the

 client connection .on the other hand both the client 1 immidiately get dropped as its IP no longer exists in  IP list on

 server vi. 2nd client seems to be stuck and then stops application and eventually get dropped from server.


  Note  server is still running if i plug in the cable again and connect my client they agin get added to server and works

           fine Which actually means that when clients get dropped there are no erros generated by  Server Vi to get


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Message 3 of 6

Code. Must see code. Need code. Mmmmmm.... code......

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Message 4 of 6

Hello madd,


I have been unable to find any information regarding this type of error or hang for the SMTP VI's specifically. If you could attach the simplest version of your code that can still replicate this error it would be useful in order to help you diagnose this issue.





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Message 5 of 6



i am out of station right now when i will get back i will attach My VI


Thnks everyone for your reply

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Message 6 of 6