[AG-TECH] Disabled Bridge

Andrew Rowley Andrew.Rowley at manchester.ac.uk
Tue Jul 20 01:51:23 CDT 2010


>From what I remember, the ping sends a TCP message (XMLRPC call of the Ping() function).  However, the bridge communicates using UDP, so the ping doesn't really test the bridge in any real way.

So what I am wondering is what you mean by "Fails to connect to the bridge".  Do you get an error message or does it seem to work but you don't see/hear anything?  Also, try running the VenueClient in Debug mode and see if there are any messages there.  If you don't get an error, it is probably a firewall issue somewhere.  One error I have been seeing a lot lately is the NoFreePortsError.  This seems to be a bug in the bridge where it is not freeing the ports in an internal data structure and so it eventually runs out.

Andrew :)


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> -----Original Message-----
> From: ag-tech-bounces at lists.mcs.anl.gov [mailto:ag-tech-
> bounces at lists.mcs.anl.gov] On Behalf Of Todd Zimmerman
> Sent: 20 July 2010 06:07
> To: Jason Bell
> Cc: ag-tech at mcs.anl.gov
> Subject: Re: [AG-TECH] Disabled Bridge
> On 07/19/2010 04:15 PM, Jason Bell wrote:
> > Todd
> >
> > My first thought is the some sort of firewall (whether at the bridge
> > or the user trying to connect to it) is causing an issue...  Having a
> > bridge "pingable", doesn't really mean that it will work.
> >
> > I have seen the issue, where the bridge say's it is disabled, but
> > changing the status to "enabled" makes it work.
> >
> > But if you change the status and it still cannot connect, I will be
> > looking else where....  Can others connect to it???  Can the bridge
> > be connected to on the same network???
> >
> Thanks for the ideas/thoughts.
> Firewall was my initial thought too... perhaps, I'll revisit/retest to
> completely rule it out.  You are correct - ping really only shows ICMP
> packets are making it through, not necessarily TCP/UDP, I'll double
> check.
> I guess my question is, what makes a bridge "disabled" in the first
> place?  Does the client actually make a TCP connection to the bridge
> service at all or is all communication with the bridge done through
> either the registry?  Suppose I could check the code, but I guess I'm
> not clear why any bridge would be disabled at all unless it was
> completely unreachable.
> For completeness, yes everyone else can connect to the bridge fine and
> it appears enabled for them.  I know I've seen similar behavior before
> to other bridges, but now that it has happened to mine, I'd like to
> track it down ;-)
> Thanks for the help/ideas - I'll follow up and get back to you all with
> any progress I make.
> Todd

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