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[netCDFJava #RAN-171087]: "javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection" for proxy connections



> I have a question concerning the netCDF-java library version 4.3.15 
> (netcdf-4.3.15.jar).
> 
> This is the netCDF-java version used by a MatLab Toolbox called nctoolbox 
> (https://github.com/nctoolbox/nctoolbox).
> 
> I use nctoolbox to access meteorological data from National Centers for 
> Environmental Information
> NCEI in grib2 format via OPeNDAP.
> https://nomads.ncdc.noaa.gov/thredds/dodsC/modeldata/cmd_pgbh/2008/200811/20081101/pgbh00.gdas.2008110100.grb2
> 
> To do so nctoolbox have to use a proxy for which nctoolbox provides the 
> function "setGlobalProxy(proxyname, port)".
> setGlobalProxy basically calls the method class method 
> "ucar.nc2.util.net.HTTPSession.setGlobalProxy(proxyname, port)" of of 
> netCDF-java.
> 
> The proxy name and port are correct according to the admins.
> 
> Unfortunately, that leads to an error java error:
> "javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
> ...
> 

Testing our proxy support code has been difficult for us since we do not have
an available proxy setup.
Our code depends on the Apache Httpclient system for handling proxies.
We upgraded to a newer version of Httpclient at some point. So, I believe you 
are
using the older version. It would be helpful if you could move to the latest
version of netcdf-Java so that you are using the latest version of Apache 
Httpclient.
Is that possible?

> 
> Our admins tried to figure out what goes wrong.
> They examined the messages received by the proxy while nctoolbox tries to 
> access the nomads database.
> The proxy receives a message he does not understand and askes for 
> authentication because he does not know anything else to do.
> The proxy normally does not require authentication.
> The message the proxy received included the proxy name some binary.
> According to the Admins, it is not something you would not expect to be sent 
> to a proxy.
> 
> If nctoolbox uses a WLAN connection without proxy the issue does not occur.
> 
> Do you know what could be the reason for this error.
> 
=Dennis Heimbigner
  Unidata


Ticket Details
===================
Ticket ID: RAN-171087
Department: Support netCDF Java
Priority: Normal
Status: Closed
===================
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