[omniORB] Binding to multiple IP addresses

[Sai-Lai Lo]

A tcp socket can always receive connection requests from all the network
interfaces. Say you have bind a socket to port 12345 and you have ip
addresses 192.168.1.1 and 25.167.200.1, then both 192.168.1.1:12345 and
25.167.200.1:12345 can be used to contact the server.

The use of -ORBpoa_iiop_name and OMNIORB_USEHOSTNAME is to control what IP
address to put into an IOR. With omniORB3, the best way to deal with
machines having multiple IP addresses is to put the hostname into the IOR
and make sure that the name is resolved to the 'right' IP address depending
on which machine the client is running on.

Suppose you have a machine that has a cluster-only nic and an external nic,
you will have to set up your machines in the cluster to resolve
foo.example.com to the cluster-only IP address and to arrange all external
machines to resolve foo.example.com to the external IP address. Once you
have done that you can just set the env variable
OMNIORB_USEHOSTNAME=foo.example.com.

Putting multiple IP addresses into omniORB3, although it is possible is not
very useful because most clients will only try one of them and give up.

omniORB4 has a more sophisticated way of dealing with multiple IP addresses
in an IOR. You can insert multiple IP addresses in an IOR. An omniORB4
client will try each of the IP addresses for each call until the call
complete. Furthermore, one can prioritise the IP addresses using a
configuration table to direct the ORB to use certain addresses in preference
to the others. I'm working on the configuration table right now so this
feature will come real soon now for people to try out.

Sai-Lai


----- Original Message -----
From: "Mark Zimmerman" <markzimm@frii.com>
To: <omniorb-list@uk.research.att.com>
Sent: Thursday, August 16, 2001 2:49 PM
Subject: [omniORB] Binding to multiple IP addresses


> Greetings:
>
> I found the documentation on this and apparemtly one can accomplish
> this by using -ORBpoa_iiop_name_port more than once. I would like to
> know if there is a syntax for accomplishing the same thing with the
> OMNIORB_USEHOSTNAME envronment variable.
>
> Also, is it valid to specify 0.0.0.0 in an attempt to get it to bind
> to all addresses?
>
> I can't experiment with this much since I don't have a multiple NIC
> machine on site but our customer has an IBM SP2 with internal and
> external interfaces and we need to manage what it uses.
>
> -- Mark
>
>
>