FMS closing the TCP connection forcibly

Hi,
I am developing an live encoder programs to publish the audio and video content to FMS. After establishing the TCP connection with FMS, when i start sending commanda and data, FMS is closing the TCP connection forcibly. Can anyone explain why is this happening?
Thanks and Regards,
Vishwanath

Hi,
If you use wireshark you can see what is happening on the wire to capture what FMS is sending (if at all) back to your live encoder program. Very very useful tool.
BTW what version of FMS are you using? Have you tried FMLE 3.2 to ensure your setup is good to go as a benchmark, this ensures you have a working FMS server ready for your own live encoder program.
I hope this helps with your debugging.

Similar Messages

Opening and closing Multiple TCP connections issues

Hi all I am having an issue with the TCP VI’s and wondering if anyone has experienced this issue.
My application is required to scan 50-100 IP addresses (statically assigned) and discover if an Ethernet device is connect at that IP address. Currently I am able to achieve this by opening a TCP connection and testing the error cluster to determine if a timeout has occurred (no timeout error means Ethernet device available at the IP address). I then ensure that the TCP connections are closed.
The issue I am have is that I require a 1 second delay between the TCP open and the TCP close which significantly slows down the process. Without the 1 second delay the vi successfully connects to the device once then fails to make any TCP connect regardless of the time delay until the PC is reset.
If anyone has any advice I would be very grateful
David Barr
P.S. I have attached a simplified section of code showing this issue
Attachments:
TCP Open close issue.vi ‏15 KB

smercurio_fc wrote:
If I understand you correctly you want the time delay to be 1 second if there's a successful connection....
While I don't have a specific answer for this problem. I want to clarify for him. I believe the issue is, what if all connections ARE there? That means you keep returning a wait of 1 second 50-100 times so It takes 50-100 seconds just to initialize. I think the user is looking for a way to check for valid connections, but do so in such a way that eliminates the need for a wait which is greatly slowing things down.
CLA, LabVIEW Versions 2010-2013

Listen if the TCP connection between robot and LV GUI is lost

Hi
I'm doing a simple client/server TCP connection between a Labview GUI and a robot controller.
My robot controller acts as the TCP server that waits for a connection from the Labview GUI, it gets a string as a ready signal and then writes a string back to the LV GUI to tell that the controller is ready, then the LV GUI should be ready to send commands to the robot.
So now first of all there are two things I want to do;
1) I want the user to push a button to connect to the robot and then make a red/green light turn on if the connection is established, then the LV GUI also starts a small loop that waits fro whatever is coming from the robotcontroller, this is only for debugging right now
2) Secondly I want the LV GUI to listen if the connection somehow is lost, like if the robot goes out of range or some other programming error in the script for the robot controller that might make the TCP connection terminate. So if the connection is lost from the serverside, then I want the LV GUI to keep runing but just turn the light red.
I have tried some of the examples in Labview but I sure could need some help on this.
LV 8.5
LabVIEW 8.6 / 2009 / 2010
Vision Development Module 8.6 / 2009 / 2010
VBAI 3.6 / 2010
Attachments:
11.gif ‏10 KB
21.gif ‏12 KB

You really should change your architecture. I assume that your other controls also control the robot, so you will need more complex messaging.
I suggest you look at some of the examples and templates for queued message handler. Essentially, this will allow you to send message between two loops, which is probably what you want.
As for what your comm loop should actually look like, you should separate the opening part from the communicating and closing part. That way, you can send the Ready string immediately after connecting. The example code you used already handles the timeout error, which is the indication you want that the connection was lost.
Here's one (very bad) example of how this could be done:
You should note that this does not really do any error handling. If you use a queued message handler and actually turn the comm loop into a state machine (with states like Open,Comm and Close), it should be cleaner.
To learn more about LabVIEW, I suggest you try looking at some of these tutorials.
Message Edited by tst on 01-19-2008 07:53 PM
Try to take over the world!
Attachments:
Comm.png ‏7 KB

How can we close the TCP connection in Extend Clients (C#)

I tried to use a C# client to connect to server side Coherence Nodes. The problem is that, Coherence creates two new TCP connections every time I create a new cache, and it never closes the connection. In the end, Coherence keeps opening hundreds connection for me, and I faced the Out Of Memory Exception.
I used Coherence Extend for the connection, and use Thread.CurrentPrincipal. I did the same thing in Java, and it works. I don't know why it doesn't work for C#.
For now, is there any way provided by Coherence to close the open TCP connection?

The issue was the AZURE_STORAGE_CONNECTION_STRING was set improperly. I was originally using the value from the 'sig' querystring value, instead of the entire signature querystring.
SET AZURE_STORAGE_CONNECTION_STRING=BlobEndpoint=https://viperprodstorage1.blob.core.windows.net/;SharedAccessSignature=<signature>
Should have been...
SET AZURE_STORAGE_CONNECTION_STRING=BlobEndpoint=https://viperprodstorage1.blob.core.windows.net/;SharedAccessSignature=sr=c&si=foobar-prod-policy&sig=<signature>
After that was set, I was able to upload.
I don't know if this mattered much, but I also changed the format of the call to...
azure storage blob upload -f "file.gz" --container "foobar-prod" -b "file.gz" --verbose

Closing the database connection after report in a server application

I searched these forums and the internet for a definitive answer on asking the Crystal SDK for java to close the jdbc connection after it has generated a report. We have been using the Crystal Report SDK to generate reports within our JEE application, built upon the Spring framework, for the past two years. It works well, especially if you prepare views in the database for your reports.
From what I can tell once you have used ReportClientDocument to create your report you all the close() method to release resources associated with report generation, but this does not close the jdbc database connection.
Further research states that if you are using the CrystalReportViewer you can call the dispose method to close the database connection. We are not using JSP nor this class, so that does us little good.
Finally I found a post that one could call ((AdvancedReportDocument)reportClientDocument.getReportSource()).dispose(). This doesn't drop the connection either.
Each report actually opens 3 connections according to SQL Server. Each report will reuse the connections it has open, so for 50 reports, theoretically, we could have up to 150 connections. We explained to our client those connections remain inactive, however this is unacceptable to our client as they would like to minimize the number of connections left open to their database.
If anyone can post any further information on this issue, it is much appreciated.

Yes, another team member found the issue. Quite embarrassing really I didn't see it. I was looking for the answer within Crystal's libraries. It had nothing to do with Crystal.
The developer who wrote the helper code for using Crystal first opened a connection to the datasource for the live production database and read that connection information for the report. Next he set that connection information in the report template's PropertyBag, then ran the report. The developer however forgot to close the connection he used to look up the connection info, leaving a memory leak and using up all the connections.
I'm glad you inquired. I forgot to post the resolution here.

Server closing the http connection

We are trying to load test our app which takes an xml message thru
          http request. The request to our app is redirected from CSS (Cisco
          content services switch) load balancer. Our app is running in a
          clustered environment with 2 servers.
          When we tried to post 100 simultaneous messages (in turn 100 http
          requests) originating from the same java client program running on
          only one machine, we get an excception "Connection reset by peer:
          JVM_recv
          Socket write error".
          All these 100 requests are simultaneous and like that we ran the tests
          4 consecutive times without any delay.
          When we ran the tests thru the weblogic proxy server (the one that
          uses HttpClusterServlet) we did not face any connection issues like
          this.
          I'm wondering if this is a load-balancer problem or a weblogic
          problem.


We're doing all the url connections thru our java program which
          creates 100 simultaneous threads which in turn becomes 100
          simultaneous posts. Someone is also suggesting that there is a time
          limit that CSS has before it received the content frame from the
          client once it opens the http connection. I'm not sure if that is
          true.
          "Vyas" <[email protected]> wrote in message news:<[email protected]>...
          > Cisco load balancer sets its own cookie to redirect traffic to the same server, this
          > cookie somehow seems to interfere with weblogic session cookie.
          > We had problems because of this in a production environment with
          > users interfering with each other's session.
          >
          > So far neither weblogic nor cisco owned up to anything , however weblogic gave us
          > a patch admitting to some problems with parsing cookies when other cookies are involved.
          >
          > I am not sure if the problems are the same for you,
          > what do you mean 100 simultaneous requests ?
          > through browser ? through httpurlconnection ?
          >
          > [email protected] (marsaroid) wrote:
          > >We are trying to load test our app which takes an xml message thru
          > >http request. The request to our app is redirected from CSS (Cisco
          > >content services switch) load balancer. Our app is running in a
          > >clustered environment with 2 servers.
          > >
          > >When we tried to post 100 simultaneous messages (in turn 100 http
          > >requests) originating from the same java client program running on
          > >only one machine, we get an excception "Connection reset by peer:
          > >JVM_recv
          > >Socket write error".
          > >
          > >All these 100 requests are simultaneous and like that we ran the tests
          > >4 consecutive times without any delay.
          > >
          > >When we ran the tests thru the weblogic proxy server (the one that
          > >uses HttpClusterServlet) we did not face any connection issues like
          > >this.
          > >
          > >I'm wondering if this is a load-balancer problem or a weblogic
          > >problem.

The TCP/IP connection does not closed after a VISA close

I am using the VISA functions to communicate with a Sorenson SGA power supply from a Windows XP computer. I have the VISA TCPIP Resource defined in MAX and use this alias name in the VISAResourceName for the input to the VISA Open. Then I write a SCPI command, such as *IDN?, and read the repsonse. Then I close the VISA session. When I look at the TCP statistics using the netstat -n command, I get the following response:
Proto           Local Address                 Foreign Address    State
TCP            10.10.10.9:3881              10.10.10.1:111       TIME_WAIT
TCP            10.10.10.9:3882              10.10.10.1:111       TIME_WAIT
If I query the ID again, I get 2 more TCP connections with different local ports numbers. Every time I perform the query, I get 2 more TCP port connections at different local ports. It takes about 1 minute for the TIME_WAIT's to time out. If I query the Sorenson enough, I can fill up my allowable local port connections.
1) Why doesn't the TCP connections go away after the VISA Close?
2) Should I be opening and closing the VISA session every time I want to talk to the Sorenson?
3) What does the VISAResourceName control or constant actual do to resolve the alias into a IP?
This Sorenson power supply does not seem to be very quick to repsond to TCP requests. If I set the timeout on the VISA Open to anything less the 100ms, I cannot get a session open every time. It will fail about 50% of the time.
Has anyone had experince talking to the Sorenson power Supplies using VISA TCPIP?
Thanks,
Julia

Hi Julia,
Let me try answering your questions here.
1) I'm actually currently looking into this to see if this is expected behavior, and I'll definitely post back to let you know what I find.
2) You do not need to close a VISA session everytime you want to communicate with the device, you can leave the same session open and keep using that session, instead closing it out at the end.
3) The VISA aliases and what they correspond to are stored in a visaconf.ini file. There is more information about this file and where it is located on your hard disk in this KnowledgeBase article here. This visaconf.ini file is checked to see what the actual resources being looked up are.
Let me know if I answered your questions, I will write back with more information on question 1.
Rasheel

How to prevent a TCP connection being closed when the VI that opened it finishes.

Hello everyone.
I am developing an application based around servers and clients communicating over TCP in LabVIEW 2012.
When the server/client opens a TCP connection ,it launches an asynchronosly running "connection handler", to which it passes the connection reference which then takes over all the communcation. This all works fine.
However - I have a situation where a client's connection handler can be informed of another "new" server. I would like it to open the connection (to see if it is still valid) and then pass this connection reference back to the client's main code to spawn a new connection handler. This prevents me locking up the Client's main code with a long-ish timeout if the "new" server is not actually accepting connections.
The issue is that if the connection handler that opened up the connection to the "new" server is stopped, then it appears to destroy the reference that it opened. This means that the other connection handler that was merrily communcating with the "new" server has its TCP communciations closed (I get an Error code 1 on a write).
I have created an example to demonstrate the issue which should be used as follows:
1. Run server.vi - it will listen for a connection on the port specifed on its BD.
2. Run CH Launcher.vi - it will open a connection to the server and pass the TCP reference to an instance of Connection Handler.vi which it launches.
3. The Connection Handler should send data to the Server
4. Stop the CH Launcher.vi
5. The Connection Handler.vi will error.
Any suggestions would be much appreciated.
Cheers
John
Solved!
Go to Solution.
Attachments:
TCP Test.zip ‏35 KB

John_Neutron escreveu:
In my case I have changes the part of the code that opens the TCP connection to a VI that has the same lifetime as the main VI so that any connections that have been opened will only be closed automatically when the main VI stops.
And what are the effects? You are still facing the same problem or closing the connection only when the whole applicaton stops solved your problem?
Regards
Mondoni

Anyone else having an issue with TCP connections using iCloud for Windows?

Hi,
Before I asked this question, I did wait to see if any related questions came up, but none did, so I submit it now.
On my admittedly older laptop running Windows 7 64b Home, I've run into difficulties with the iCloud for Windows app to the extent that I had to uninstall it.
It would that, as my laptop was running, in the background, iCloudServices.exe would endlessly iterate TCP connections, which, while not actively sending or receiving any data, after some hours would number over 100 instances, taking up resources, and grinding my laptop's WiFi connection to a grindingly slow pace. I ended up, within the app, turning off everything, iCloud Drive and Photos, (I never used bookmarks), but still this would continue to occur.
I contacted Apple Support, explaining what was going on, and they stated they only dealt with IOS and gave me a Microsoft Support number. When I called Microsoft support, I came more and more to the realization that the issue was specifically with the iCloud for Windows app, as that was the only software that was endlessly creating and not closing TCP connections as it was. How was Microsoft supposed to solve an issue with Apple code?
So I called Apple back, whereupon they insisted it was a Microsoft issue. I explained other cloud services installed on the same computer were not having the same issue, it was unique to ICloudServices.exe. They stated they only dealt with IOS. I stated I purchased an iPad Air less than 7 months ago, and was trying to run iCloud in support of that. They again stated they only dealt with IOS, and suggested I again try Microsoft. I asked them if it was reasonable to expect Microsoft to solve issues with Apple code? They said regardless, there was zero support offered for anything having to do with Windows, and all I could do was uninstall the app, which I did, though that did not feel very satisfactory to me. My thinking is, if Apple writes a Windows app in support of their hardware, they should offer support for it.
Anyway, I was just wondering, is this an issue unique to me? or have others experienced a similar issue? I found this issue by opening the Windows Resource Monitor, looking under the Networking tab, and scrolling through the TCP Connections section to find 100+ concurrent iCloudServices.exe instances listed, whereas even Chrome, with multiple tabs and extensions, topped out at around 20.
My one month old Desktop, DYI, sports a solid Asus 1150 MoBo, i7-4790k cpu, 16GB Ram, and an EVGA GTX 970 video card. I list some specs only to illustrate this computer has no hardware issues in comparison to my long in tooth laptop. On this desktop, running Win 8.1 Pro 64b, at least as many, identifiably Apple, background service TCP connections are created even compared to Chrome, regardless of many tabs being open, many extensions, and even some related apps. Adobe does not even come close, though I run the full CC subscription. On this new computer, running Windows 8.1 Pro 64b, there are currently over 50 TCP connections and loopbacks that do not identify themselves, with just a - for the Image, and PID. With the experience on my laptop, I wonder how many of these are generated by Apple software, if not specifically iCloud software?
The frustrating aspect of these connections is they seem in no way active, While the Chrome and Adobe connections can be seen to be transferring data, as long as I am not running iTunes, or so have my iPad actually plugged in, it seems 99% of the time these iCloudServices.exe connections are just taking up ports, neither sending nor receiving any data discernable to me under the Processes with Network Activity, or Network Activity lists, both displayed in the same window as the TCP Connections in the Windows Resource Monitor.
Though I am fairly ignorant as regards coding, it seems as if there is no call to close a connection, very specifically, iCloudServices.exe, when it is no longer needed, and the next time a connection is needed, a new one is opened, rather than accessing the one previously opened. The only other reason I could imagine this might be occurring is if my Norton Internet Security software might mask and/or block the port after a certain time of inactivity.
Anyone out there have any ideas or advice about this? Thanks in advance.

Thanks jared,
I'm still dealing with this issue through Apple. Some time after I posted this, I contacted Apple again. They did start a case up for me, as I was experiencing the same behavior on two different machines, with two different versions of Windows.
So far it remains unsolved. I've logged iClouds for Windows on my desktop, which is brand new, then logged for awhile after completely uninstalling Norton Security Suite, depending on the Microsoft security for some time, and finally logged after I uninstalled iCloud for Windows, restarted, installed a clean download, and connected using a completely different test account, which Apple set up for me. None of this made any difference. Looking at the logs, it seems every 10 minutes, iCloudServices.exe creates a new TCP connection to confirm I'm using less than 5GB on iCloud, (which I am by a good margin, using less than 2GB), it seems this connection is not closed, and when the next iteration rolls around 10 minutes later, a new TCP connection is created. I come very close to having 6 TCP connections created per hour, until I restart my computer. This works out to... 6 x 24 = 144/day.
Perhaps the article you posted will shed some further light on this. I'm thinking seeing the state of the connection through netstats, at the least, could help.
For the last week, I've been putting a hold on further logging, as Apple wants me to create a new user account on one of my computers, install iCloud for Windows there, and log it running in the other account. This however basically means I cannot use my computer for a fair number of hours, and I've been busy enough with work the past week that I haven't the time or energy to afford to set this up and run it. I've had need of my computers too much for the past week.

SbRIO-9612 unable to close a TCP connection without causing TCP failure

Hello,
I'm working on a multi-server (sbRIO-9612's), multi-client (Windows PCs) application which uses the STM 2.0 libraries and LV2009 SP1. The server listens on a UDP port for the client to send a message - once sent, the server opens the TCP connection to the client and all is well . . .
. . . until I added a "hearbeat" message to monitor for down connections. Once the TCP connection has been extablished, the client PC sends a TCP message (a request for the number of clients connected) to the server sbRIO-9612 every 5 seconds - both the client and server are coded to close the connection if a message is not received within 10 seconds. The client-side app works fine - if the TCP message is not returned in 10 seconds, the connection is closed and a new UDP message is sent to re-establish it.
The server-side is the problem - if no message is received in 10 seconds, the TCP connection is closed o.k. (no errors), but the server will no longer allow new TCP connections to be established unless it's rebooted. It seems to work fine if I leave the non-communicating TCP connections open on the server-side, but I can see this leading to problems after several clients have disconnected without notifying the server properly.
Interestingly, if the client closes the TCP connection properly (via TCP Close in LV), the server detects it fine and there is no problem.
I'm allowing the operating system on both sides to select the TCP port to use.
Any help is greatly appriciated - thank you!
Al

Hi Al,
Thanks for the update -- I'm glad that you were able to find that the issue wasn't actually with the TCP VIs, and moreover that LabVIEW 2010 SP1 seems to have resolved the issue. I would still recommend combing through the code on the RT end to ensure that the LabVIEW 2010 SP1 upgrade really did 'fix' the underlying issue. It's somewhat strange that a version upgrade resolved TCP communication issues that you were having. I just want to be sure that the solution is a truly stable one.
Sanjay C.
Embedded Software Product Manager| National Instruments

TCP connection for DHCP failover frequently are broken in Solaris 10

Hi
We have two dhcp servers which are installed in Solaris 10 and set to a failover pair. Currently, we can find that tcp connection for dhcp failover protocol are frequently broken. It looks like that primary dhcp server initiatively send FIN message to secondary one but in general, this tcp connection should always keep alive. On the other hand, the tcp connection can not completely be closed right now which FIN_WAIT_2 status in Primary one and CLOSE_WAIT status in secondary would last for a long time.
Will Solaris 10 cause this fault? Is it a known bug in OS?
OS info:
-bash-3.00$ cat /etc/release
Solaris 10 5/08 s10s_u5wos_10 SPARC
Copyright 2008 Sun Microsystems, Inc. All Rights Reserved.
Use is subject to license terms.
Assembled 24 March 2008
-bash-3.00$
-bash-3.00$
-bash-3.00$ uname -a
SunOS edns1 5.10 Generic_142900-03 sun4v sparc SUNW,Netra-T5220
TCP connection info:
Primary DHCP Server:
2012 08 29 03:41:43
PING 172.25.6.137: 56 data bytes 64 bytes from edns2 (172.25.6.137): icmp_seq=0. time=0.678 ms
remote refid st t when poll reach delay offset disp
==============================================================================
*idns1           195.26.151.151   3 u   45 1024 377     0.75   -0.071    0.05
+idns2           195.26.151.151   3 u 162 1024 377     0.93    0.169    0.08
clusternode1-pr 0.0.0.0 16 - - 1024 0 0.00 0.000 16000.0
+clusternode2-pr idns1            4 u 406 1024 376     0.49   -0.154   15.12
172.25.6.133.647 172.25.6.137.58107 49640 0 49640 0 ESTABLISHED
172.25.6.133.647 *.* 0 0 49152 0 LISTEN
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2012 08 29 03:41:47
PING 172.25.6.137: 56 data bytes 64 bytes from edns2 (172.25.6.137): icmp_seq=0. time=0.535 ms
remote refid st t when poll reach delay offset disp
==============================================================================
*idns1           195.26.151.151   3 u   49 1024 377     0.75   -0.071    0.05
+idns2           195.26.151.151   3 u 166 1024 377     0.93    0.169    0.08
clusternode1-pr 0.0.0.0 16 - - 1024 0 0.00 0.000 16000.0
+clusternode2-pr idns1            4 u 410 1024 376     0.49   -0.154   15.12
172.25.6.133.647 172.25.6.137.58107 49640 0 49640 0 FIN_WAIT_2
172.25.6.133.647 *.* 0 0 49152 0 LISTEN
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Secondary DHCP Server:
2012 08 29 03:41:41
PING 172.25.6.133: 56 data bytes 64 bytes from edns1 (172.25.6.133): icmp_seq=0. time=1.26 ms
remote refid st t when poll reach delay offset disp
==============================================================================
*idns1           195.26.151.151   3 u 450 1024 377     0.92   -0.067    0.06
+idns2           195.26.151.151   3 u 552 1024 377     0.96    0.237    0.08
+clusternode1-pr idns1            4 u 360 1024 377     1.85   -0.528    1.51
clusternode2-pr 0.0.0.0 16 - - 1024 0 0.00 0.000 16000.0
172.25.6.137.647 *.* 0 0 49152 0 LISTEN
172.25.6.137.58107 172.25.6.133.647 49640 0 49640 0 ESTABLISHED
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2012 08 29 03:41:45
PING 172.25.6.133: 56 data bytes 64 bytes from edns1 (172.25.6.133): icmp_seq=0. time=1.36 ms
remote refid st t when poll reach delay offset disp
==============================================================================
*idns1           195.26.151.151   3 u 454 1024 377     0.92   -0.067    0.06
+idns2           195.26.151.151   3 u 556 1024 377     0.96    0.237    0.08
+clusternode1-pr idns1            4 u 364 1024 377     1.85   -0.528    1.51
clusternode2-pr 0.0.0.0 16 - - 1024 0 0.00 0.000 16000.0
172.25.6.137.647 *.* 0 0 49152 0 LISTEN
172.25.6.137.58107 172.25.6.133.647 49640 0 49640 0 CLOSE_WAIT
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Thanks!

Thanks, but had found a previous discussion with this hint and applied it.
svccfg -s sendmail listprop shows config /local_only = false
Yes, I would really love to fix the fault, but what I would really like is some hints as to how to debug ports under svc control.

Proper method to reset tcp connection after timeout error

I have a application that I am building that communicates with a Modbus TCP device. If a communications error occurs I would like to be able the reset the TCP communications. What I have is a control that fires a event when pushed. In this event I have a sequence that first closes the tcp connection and then opens a new connection. My applications starts and runs fine. To test the reset function I removed the ethernet cable from the device and waited of a timeout to occur. I plugged the cable back in and pushed my reset control. Occasionally the reset will occur but most times I will get a time out error at the Open TCP vi. After this, the only way I can establish communications is to exit my application, disable and then enable my network device. Then when I restart my application I have communications with my device.
Any help would be appreciated on how I should be resetting my TCP connection.
Thanks
Terry
Solved!
Go to Solution.

Terry S wrote:
I have attached a example vi (LV10) that shows just the TCP connection and Reset. An error will occur when trying to perform the open tcp in the reset event.
As written your code should be fine. There is nothing inherently wrong with it. However depending on the device you are communicating with you may be trying to reestablish the connection too quickly after you closed the connection. The device may not allow multiple connections to it and may require sometime to clean things up on its end after you close a connection. As an experiment trying waiting a short time between the TCP Close and the TCP Open. If possible you may want to try using Wireshark to see what is happening on the network. It can be useful in diagnosing what is going on.
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot

Windows XP doesnt detect broken TCP connection

Hi Guys,
I have a client and a server. When they are both on a linux or both on a Windows machines there is no problem.
When the server is on linux and the client is on Windows XP, when the server goes down, the client does not recieve a SocketException.Connection Reset like it should.
It works fine otherwise, does anyone know why Windows cant see the TCP connection breaking if the server is on linux?

Java's platform independence cannot shield you from all variations in the implementation of the TCP/IP stack in the underlying operating system.
If you need to do special tricks for different operating systems chances are you are doing something in a non-optimal way. For the vast majority of programmers TCP/IP "Just Works". You open your sockets, do I/O on them, eventually close them.
If you write into a socket whose peer has done receive shutdown you eventually get an IOException (I'll guesstimate within one or three minutes absolute worst case). If you don't get the IOException then likely your program has a bug, such as ignoring exceptions. Far lesser likelihood is OS bug.
When you say "server goes down" do you mean the OS goes down (as in unplug the network connector), or the OS is shut down with a "shutdown" command, or the program is closed? TCP/IP will behave differently if the remote OS is forcefully brought down vs. the program exits and OS remains running. A "shutdown" command may exhibit either behaviour, depending on OS implementation and random timing effects.

TCP connections used by RMI

hello,
I tried making a simple RMI application to check about the usage of TCP connections for the communication. The client and server are running on different hosts and my observations are:
a) when the client is invoking a method on the server at an interval of about 1 sec, then the same connection is used everytime for the communication.
b) when the client is invoking a method on the server at an interval of about 30 sec, then the a new TCP connection is made everytime for the communication !
The java.rmi.dgc.leaseValue is set to 100 minutes in both cases. Does this not mean that the connection should be maintained for 100 minutes even if there is no communication between the client and server ??

thanks, I could not find any parameter in the standard properties list, however in the SUN specific properties we do have sun.rmi.transport.proxy.connectTimeout which should control the connection life. I use IBM's JRE, so I will try to find an equivalent property.
Another question ... what is the benefit of java.rmi.dgc.leaseValue if the TCP connection is closed itself ? Does the gc not happen if the TCP connection itself breaks ? Or does the RMI think about a logical connection which is independent of TCP connection's life ?

Router closes TCP connection after 30 minutes

I have recently replaced my D-Link DIR-100 router with a Cisco Linksys RV042, but unfortunately there seems to be a problem with it.
I have an external TCP connection coming in to a local service, and I therefore set up the router to redirect the incoming connection for the given port to the local PC hosting the service. This worked perfectly. I also opened the Firewall access rules to allow all data from WAN2 to be propagated through. This also worked just fine, and I can connect from the internet to the local PC, just like I could with my old router. Unfortunately this is where the simularities stop. When there is no communication on the TCP connection for more than 30 minutes then the router closes the connection automatically. This is NOT what I want. I only communicate on the TCP connection very rarely, but I do not want it closed automatically - at least not after just 30 minutes.
I did some research on line and it appears that there in some routers are a TCP connection timeout, which in the router I read about, defaulted to 1 day. This would be OK. I experimented and found that if there is communication every 30 minutes then it is not close the connection, but if there is 50minutes between communication then it closes the connection.
As I read that this timeout has to do with security I experimented with the firewall and found the following:
1. Disabling the entire router firewall fixes the problem !!!
2. Disabling just DoS has no effect (problem still exists)
3. Disabling SPI means I cannot connect at all !!! (new and much worse problem)
4. Disabling Block WAN Requests has no effect (problem still exists)
Is there a way to solve this problem without disabling the entire firewall, as that is not what I want to do. I have the system set up for Dual WAN (load balancing), and I only want to allow connections to a handful of ports on the one WAN, and block the other WAN entirely.
P.S. I was referred to the Cisco Small Business Support Community by the Cisco Home community, so I hope this is the right place.

Hi Ddb101,
This is a limitation (or feature depending on how you look at it) of the iPhone/iPod touch. 30 minutes after the device locks (usually 5 minutes of inactivity) the network turns off completely to save battery life. You can either turn autolock off globally, or some programs (mine for instance see: http://ootunes.com/app/ ) have an option that disables sleep while the app is running so the stream will keep playing... until your battery dies Only problem is with the screen on the battery actually dies even faster!
Finally, if the device is connected to a constant power source, it shouldn't actually time out. So if you have a way to plug it in, it shouldn't quit after 30 minutes on you...
hope that helps,
also, since there's a link to my site up there, and I sell the app, I should tell you that I might get money if you go to the page and end up buying my app...

FMS closing the TCP connection forcibly

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