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. 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()); > > } > > } > > > > > > > > > > > > > > -- Vince Stewart
