Re: Full loop to public IP and back

[Aaron Bartell <aaronbartell@xxxxxxxxx>]

> My question is why?

Good question.  Imagine a galaxy of inter-connected IBM i machines where
they are starting/stopping services (applications or otherwise) via RESTful
HTTP request and in some cases, based on DB configuration, the service
might be on the same machine; but the machine doesn't care that it's
starting something on itself, it just needs a URL.  [Aaron checks "run-on
sentence" off his bingo card]

> It is an issue with the NAT for the outbound connecting to itself.

Will look here next.  I have access to the firewall admin interface (VMware
vCloud).



Aaron Bartell
litmis.com - Services for open source on IBM i


On Tue, Jan 19, 2016 at 8:26 PM, Chris Bipes <chris.bipes@xxxxxxxxxxxxxxx>
wrote:

> My question is why?  To access the web service on a local machine you
> should be able to use its loop back or local IP.  A lot of firewalls will
> prevent you from accessing your public IP from your private.  Even if they
> are wide open.  It is an issue with the NAT for the outbound connecting to
> itself.
>
> Chris Bipes
> Director of Information Services
> CrossCheck, Inc.
>
> -----Original Message-----
> From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
> Aaron Bartell
> Sent: Tuesday, January 19, 2016 6:03 PM
> To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
> Subject: Full loop to public IP and back
>
> I have a machine named KT1.  While on KT1 I am trying to call a web service
> using its public IP - essentially calling myself by first going out to the
> internet and back again.  The issue is it times out.  I can access the
> public IP (and web service) from many other computers but not from within
> the same machine (KT1).  From KT1 I can access other public IPs, just not
> its own public IP.  I've configured the firewall to be wide open so I don't
> think it's that.
>
> I've tried adding the public IP to CFGTCP opt 1 and opt 10 (with applicable
> domain) but nothing I do seems to be working.
>
> *Questions:*
> 1 - Do I need to restart TCP/IP services on IBM i after making CFGTCP
> changes?
> 2 - Is there something obvious I am missing?
>
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