IP, hostnames and DNS issues

IP, hostnames and DNS issues

Post by Jan Jonase » Thu, 29 Apr 2004 15:55:52

(recently sent to openorb-users, but no reply)
I'm having an issue with the speed of communication between client and
server with the following setup:
OpenORB 1.3.1
Client: Java client running on Mac OS 10.3.3, JDK 1.4.2_04. Not in the
local DNS nor servers host file.
Server: Windows 2000 server, JDK 1.4.2_02. This is in the local DNS.
Nameservice started with the following parameters:
java -Dorg.omg.CORBA.ORBClass=org.openorb.CORBA.ORB
-Diiop.publishIP=true org.openorb.tns.Server -ORBPort=14100 -printIOR

So far it seems it's the server having issues communicating back to the
client, because adding the client to either DNS or the servers host file
makes it run just fine.

As you can see above I've tried utillizing the iiop.publishIP setting,
besides as above it's also set to true in default.xml, same has been
done on the client. I've also tried setting it to false for all
components because of reading about a bug causing it to have revers
meaning. Having both client and server printing their IOR and parsing
this with an omniorb app, suggests these are indeed including IPs rather
than hostnames.
It should be mentioned running the same client in a pure Windows
environment acts as if the client was in DNS, I suppose Windows resolves
the names internally by WINS or similiar.

1. How can I determin with a 100% certainty all communication is done by
2. Where do I look for the problem server side or on the client?
3. Is there some (other) way to force the IP only communication?
4. Since the communication eventually takes place, how can this be?

The problem looks very similiar to this:
mentioned the iiop.publishIP doesn't seem to do the job.

Thanks in advance and best regards

Jan Oksfeldt Jonasen

1. vb script to retrieve DNS records, identify hostname and ip duplic

2. How does WebClient use the multiple IP addresses that can result from a hostname DNS lookup?

Hi there,

I was wondering if someone could point me in the right direction with
how the .net 2.0 frameworks WebClient class uses the multiple IP
addresses that can be resolved when a hostname is looked up.

To frame the question, look at a dig for www.google.com:

;www.google.com. IN A

www.google.com. 154705 IN CNAME www.l.google.com.
www.l.google.com. 300 IN A
www.l.google.com. 300 IN A
www.l.google.com. 300 IN A
www.l.google.com. 300 IN A

l.google.com. 43689 IN NS f.l.google.com.
l.google.com. 43689 IN NS g.l.google.com.
l.google.com. 43689 IN NS a.l.google.com.
l.google.com. 43689 IN NS b.l.google.com.
l.google.com. 43689 IN NS c.l.google.com.
l.google.com. 43689 IN NS d.l.google.com.
l.google.com. 43689 IN NS e.l.google.com.

You can see that www.google.com resolves to www.l.google.com, which in
turn resolves to four different ip addresses.

What I would like to understand is how WebClient uses these four
different addresses.

Also, I would like to use this mechanism to provide a "last line of
defence" availability strategy. If WebClient does support using these
multiple addresses, is it possible to control how it uses these
addresses? I mean, I would like to have some control over the way the
webclient fails over between the different addresses.


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