Here[^] you can read the description for WSAECONNRESET: Connection reset by peer. An existing connection was forcibly closed by the remote host. This normally results if the peer application on the remote host is suddenly stopped, the host is rebooted, the host or remote network interface is disabled, or the remote host uses a hard close (see setsockopt for more information on the SO_LINGER option on the remote socket). This error may also result if a connection was broken due to keep-alive activity detecting a failure while one or more operations are in progress. Operations that were in progress fail with WSAENETRESET. Subsequent operations fail with WSAECONNRESET. My guess is that for some reason the client closes the connection (crashes?), or maybe "something" on the machine of the client closes the connection. Does the client maybe generate any log? > The problem with computers is that they do what you tell them to do and not what you want them to do. < > Leela: Fry, you're wasting your life sitting in front of that TV. You need to get out and see the real world. Fry: But this is HDTV. It's got better resolution than the real world <

Ok, sounds like a design or cost problem. Unfortunately, I see no other technical solution than the one mentioned before. The concept of a heartbeat is more or less the same regardless of using UDP or TCP. If peer A wants to know about the status/availability of peer B, it either has to receive a "message" from B in regular intervals (and therfor knows that peer B is alive) -or- when there is no regular traffic to piggyback the heartbeat then one of the peers has to initiate (additional) heartbeats in reasonable intervals. For example an IRC server uses regular ping/pong messages every few minutes to find out about the connection status of its chat clients. Regarding the costs, at the end of the day a better service will cause more traffic. You could offer your customers maybe a cheap basic service and an advanced service with more features. Hope this helps /M Webchat in Europe :java: (only 4K)

A port represents a way to identify which specific process a packet is addressed for on a system where multiple processes share the same network connection. Therefore ports are generally an application level mechanism. If the mobile device does not use this typical approach then I don't know what it uses, but someone does that would be related to that specific device. In a typical use of a TCP/IP stack the application can choose to be assigned a random port from the stack. In that case the "where" is in the TCP/IP stack code. Either way, I don't understand how knowing "where" the port assignment occurs helps you do anything about it. That aspect of the mobile devices system is not going to be exposed to your remote application. You will have to use the specifications for that device/application, as I previously stated, for communicating with it/them, period. led mike

Good point, but what if the PC restarts for any reason (windows crash, power...)

Unfortunately, this information is not provided with UDP. You need to implement a heart beat (or use an existing library that does it for you). Maybe you can implement a simple solution where the Windows application will mark any mobile device "disconnected" which hasn't sent anything within a time intervall. The next time the mobile device sends something it will be marked "connected" again. Hope it helps! My Webchat

Thanks a lot, worked perfectly! Thanks thanks thanks,

Of course...It really didn't sound like it needed that kind of accuracy. Checking once a minute for 00:00 might be sufficient. Or check every second and catch the first midnight rollover. Or it could sit in a busy loop monitoring the atomic clock in Colorado. I just threw the option out there :) Cheers, Mark Mark Salsbery Microsoft MVP - Visual C++ :java:

nahitan wrote: I am working on a system that sends receive messages via TCP sockets and I need to have a way to inform a service person if the link is down from one application to the other by sending a text message (email, SMS). The application that sends and recive messages in writen in C++ but I am not sure how I can add this feature to it. Also I was thinking if I could have a second application that would watch the first one for connection integrity. Could anyone please give me some help (any tutorial, code sample...) there are many SMS gateway available on net. which can help you in same.. look at cellebrum.com "Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow cheers, Alok Gupta VC Forum Q&A :- I/ IV Support CRY- Child Relief

You said you check for does your program is exist or no I think some days ago I saw a thread on the codeproject about this search on the comments for see this thread.:) WhiteSky

Yes! Any .DLL you load becomes a part of your code, not a seperate process. This is a curious question, because throughout all coding, if your code creates or loads something, your code is also responsible for managing and destroying that something properly. Making the assumption that an object or runtime can clean itself up without you telling it to do so is a very bad thing to do. This practice leads to unstable applications and operating systems. For instance, if you application creates a Graphics object, you are also responsible for destroying it when your done with it. If not, you'll eventually run the system out of resources and crash the whole operating system. Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic      2006, 2007

See: http://www.tangentsoft.net/wskfaq/newbie.html#normalclose[^] ...cmk Save the whales - collect the whole set

Send data in regular intervals, if the connection is down you will be notified (TCP write operation returns error). My Webchat

Thanks for the tip. Best regards

Thanks a lot!

As far as i know, i think it can be done using GSM modem and AT commands. KIRAN PINJARLA

I don't think VB has any password Dialog Forms pre made so you would have to build a new form with a password box and pop it up when the unload event is raised. Then you can check the password with the hardcoded one. Kevin

nahitan wrote: ...the 2nd applicstion does not check the header that actually is there containing the mobile id, group id. Bummer :)

Thanks :)

In addition to what David said, you can still use your debugger to narrow the problem (it's much faster to get information from your debugger than through a forum for these kind of problems). Cédric Moonen Software developer Charting control [Updated - v1.1]

You could wait until the TCP/IP stack reports that the connection is down (can take very long). Alternatively send a small connection testing packet (e.g. smilar to IRC's PING/PONG mechnism), sometimes you will receive immediately an error saying that the connection is down... or you can timeout the connection if you haven't received a connection test packets from the other peer for a while. [corrected typos] :)