[Mulgara-general] RMI server not running?

[Paul Gearon]

On 6/12/07, Gok Mop <gokmop at gmail.com> wrote:
<snip/>

Yes -- forwarding both UDP and TCP traffic.  In my case, traffic that comes
> in should go to internal address 192.168.1.101 (the linux machine)
>

So what happens if you try to connect from your internal network to the
local machine via the external address?  ie.  If your external address is
1.2.3.4, and this is forwarded to 192.168.1.101, then on the machine
192.168.1.101 can you do an ssh (or http, or whatever service you have
available) to 1.2.3.4?  Many routers won't let you do this.

What should happen is that the connection request will be recognized as
non-local, and go to the router.  At this point, there are two choices:
- A simple router configuration will realize that the packet is destined for
the public network and send it that way.  The ISP will recognize that the
packet came from it's destination, and drop it, since it has already been
where it needed to be.
- A better router configuration will recognize that the destination is
itself on another interface, and send the packet into an internal ipchain,
where it will be remapped, and sent back it with the new address of
192.168.1.101.


In any case, it probably isn't mulgara.  Still, assuming this speculation is
> > > related to my problem, it would be nice if mulgara didn't try to change the
> > > hostname on me...if it would just use the hostname or IP address I give it
> > > through configuration or URIs.
> > >
> >
> > How do you think it is changing the hostname?
>
>
> Case in point:
> My externally valid internet IP address let's say is 1.2.3.4.  My internal
> address is 192.168.1.101.  I start mulgara telling it that the machine it
> is on is "localhost", 192.168.1.101, and "foobar.dyndns.org".  (Through
> host configuration, not mulgara specific)
>
> I fire up the webui, and the URI it wants to use is rmi://c-
> 1-2-3-4.hsd.ny.comcast.net/server1#sampledata
>

I hate the WebUI.  It's broken.  I know it's in the documentation, but I
really recommend that you don't use it.  Certain configurations can cause it
real grief, and it looks like yours might be one of them.

<rant>
It should be fixed, but I don't have time.  So I want to remove it, but no
one will let me.  But those same people who won't let me can't be bothered
to fix it for themselves.
</rant>

If you want to make it work, then try using the iTQL shell.  If that doesn't
work, then I'll be happy to help you work it out.  The shell is easy to
start:

# java -jar itql-1.0.0.jar

This is a Swing console.  If you'd rather use the command line, then the
itql jar also accepts commands in a script file:

# java -jar itql-1.0.0.jar -s myscriptfile.tql

(This hostname is what you would get if you tried to resolve a hostname from
> my externally valid IP address)
>
> If I change the host in the URI to foobar.dyndns.org, then when I submit
> the query, the error message that will come back complians about not being
> able to connect to RMI on c-1-2-3-4.hsd.ny.comcast.net.
>
> What I'm saying by way of the speculation from earlier is this -- it's
> normally resonable to use those hostnames interchangably, (since from an
> external perspective they resolve to the same thing) but since the linux
> machine knows itself as foobar.dyndns.org and not as
> c-1-2-3-4.hsd.ny.comcast.net, whether or not this will actually work will
> depend on arcana of how my home router does port forwarding.
>
> Some kind of transparent lookup is happening that I can't control.
>
> Thoughts?
>

Try the shell.  It will make connections based on the name you use in the
graph URIs.

Paul
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