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From Christofer Dutz <christofer.d...@c-ware.de>
Subject Re: [Netty / S7] Many log messages although everything works
Date Fri, 12 Apr 2019 13:24:04 GMT
Hi Otto,

when inspecting the TCP traffic, for example Siemens LOGO devices tend to just hang up without
sending a TCP ack if they get something they don't like.
It's not TCP compliant, but it's the way they roll :-(

So I know when trying to access a LOGO device with the S7 protocol, I had to disable the part
where the driver tries to find out what type of PLC he is talking to because of this ... don't
really know how we can counter-react this situation ... 

How about me adding the Exception handler and simply logging things there so we can define
a breakpoint and try to find out what's going on?

Chris



Am 12.04.19, 15:06 schrieb "Otto Fowler" <ottobackwards@gmail.com>:

    I would think you’d want to handle it, and then investigate the reason for
    it in this instance
    
    
    On April 12, 2019 at 08:51:05, Christofer Dutz (christofer.dutz@c-ware.de)
    wrote:
    
    Hi Otto,
    
    I think the English translation would be something like:
    
    "Connection reset by remote" or "Connection reset by peer"
    
    Not sure if this helps understand what's going on ... I always thought it
    was related to
    the PLC hanging up without following the correct procedure for doing that.
    Sort of like
    just hanging up the phone without saying goodbye.
    
    Perhaps really implementing an exception handler and just swallowing the
    exception
    Because we know we're operating in "unpolite" environments ... but not sure
    what
    We could do to gracefully handle the situation.
    
    @Julian ... would it be ok to catch that and simply log an "INFO" severity
    message ("Remote hung up unexpectedly")
    
    Chris
    
    Am 12.04.19, 13:52 schrieb "Otto Fowler" <ottobackwards@gmail.com>:
    
    The netty handlers don’t implement exceptionCaught so the default is to
    spew to logs. I don’t speak german so I don’t know what the exception
    message is.
    Maybe the handlers should implement the method.
    
    
    On April 12, 2019 at 04:56:40, Julian Feinauer (j.feinauer@pragmaticminds.de)
    
    wrote:
    
    An exceptionCaught() event was fired, and it reached at the tail of the
    pipeline. It usually means the last handler in the pipeline did not handle
    the exception. java.io.IOException
    

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