On Mon, 2013-02-04 at 17:51 +1300, Vince Stewart wrote:
> Hi Tim,
> thanks so much for your reply
> netstat -t -l  yields that includes:
> Active Internet connections (only servers)
> Proto     Recv-Q  Send-Q    Local Address                       Foreign
> Address         State
> tcp6       0          0              myComputerName:4000
> [::]:*                        LISTEN
> netstat -atn | grep -P ":4000\W"  yields (without any headings line)
> tcp6       0          0              127.0.1.1:4000
> :::*                          LISTEN
> 
> re But why would you want that limitation?
> My first aim was to send a single message from home to my VPS or vice
> versa. When I did not succeed I have been fishing for reasons and the first
> thing that struck me was that Ubuntu was reporting tpc6 but NioReceiver
> object "clusterReceiver" had a "bind" property of type Inet4Address and an
> address of 2130706689 (127.0.0.1).
> 
> Possibly though, this is a normal IPv6 connection and I should treat it
> accordingly. I'll give that ago tomorrow morning and keep CATALINA_OPTS in
> mind as well.
> 

Yes, I believe this is normal.  Looks like your system is using
"IPv4-mapped addresses" which allows interoperability between IPv4&6
hosts without needing two IP stacks on the IPv6 host.

> Many thanks for your help.
> 
> 
> 
> 
> On Mon, Feb 4, 2013 at 4:06 PM, Tim Watts <t...@cliftonfarm.org> wrote:
> 
> > On Mon, 2013-02-04 at 14:39 +1300, Vince Stewart wrote:
> > > Using Tomcat 7.0.35 embedded in Java standalone application. Java SE
> > 1.7.0.
> > > Ubuntu 12.04
> > >
> > > Hi All,
> > >
> > > I have an experimental class below. The aim is just to open a listening
> > > port on port 4000 in the "localhost" address.
> > > When this has run, the address for the listener is "127.0.0.1" in other
> > > words an IPv4 address.
> > > However the SocksSocketImpl object representing the real socket continues
> > > to display the* useV4* property as *false*
> > > and my Ubuntu system displays the listening socket as "tpc6".
> > >
> > Listening only for tcp6?  What does
> >         netstat -atn | grep -P ":4000\W"
> > show?
> >
> > Perhaps what you want is to set the java.net.preferIPv4Stack system
> > property in CATALINA_OPTS?  Description here:
> >
> > http://docs.oracle.com/javase/7/docs/technotes/guides/net/properties.html
> >
> > But why would you want that limitation?
> >
> >
> > > I suspect there is some configuration issue somewhere and if anyone can
> > > help with this, I would be most grateful.
> > >
> > > I have also noted that the java.nio.channels.spi.SelectorProvider cannot
> > > return a Provider from loadProviderFromProperty() or
> > loadProviderAsService()
> > > so therefore issues *provider =
> > > sun.nio.ch.DefaultSelectorProvider.create()*resulting in a
> > > ServerSocketChannel that is of type
> > > *sun.nio.ch.ServerSocketChannelImpl*
> > > and a ServerSocket of type *sun.nio.ch.ServerSocketAdapter*. I'm not sure
> > > that these are intended and may be I need a system property named
> > > "java.nio.channels.spi.SelectorProvider" to ensure some other
> > > SelectorProvider and therefore different ServerSocketChannel and
> > > ServerSocket types.
> > >
> > > public class TribalAfiliations{
> > >  Channel myChannel;
> > >  private static class MyMemberListener implements MembershipListener{...}
> > >  private static class MyMessageListener implements ChannelListener{...}
> > >
> > >  TribalAfiliations() throws SocketException{
> > >  this.myChannel=new GroupChannel();
> > >  ChannelListener msgListener = new TribalAfiliations.MyMessageListener();
> > >  MembershipListener mbrListener = new
> > TribalAfiliations.MyMemberListener();
> > >  myChannel.addMembershipListener(mbrListener);
> > >  myChannel.addChannelListener(msgListener);
> > >    try{
> > >
> > >
> > myChannel.start(Channel.MBR_TX_SEQ|Channel.MBR_RX_SEQ|Channel.SND_TX_SEQ|Channel.SND_RX_SEQ);
> > >    /// same problem, with    myChannel.start(Channel.DEFAULT);
> > >    }
> > >    catch(ChannelException e){
> > >    System.out.println(e.getMessage());
> > >    }
> > >  }
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> 
> 

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