Re: Full loop to public IP and back

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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