Re: Service naming in Net Manager

From: Billy Verreynne <vslabs_at_onwe.co.za>
Date: Tue, 10 Jun 2003 11:07:05 +0000
Message-ID: <bc477g$lp6$1@ctb-nnrp2.saix.net>

Peter wrote:

> Something like this in the TNSNAMES.ORA file
> db =
> (DESCRIPTION =
> (ADDRESS_LIST =
> (ADDRESS = (PROTOCOL = TCP)(HOST = db.domain)(PORT = 1521))
> (ADDRESS = (PROTOCOL = TCP)(HOST = db.domain)(PORT = 1522))
> (ADDRESS = (PROTOCOL = TCP)(HOST = db2.domain)(PORT = 1521))
> )

Ah.. interesting. Sybrand, try the above. In fact you can configure multiple ports for the _same_ listener (I've always configured separate listeners).

I changed my DEV listener to:

    (DESCRIPTION =

      (ADDRESS = (PROTOCOL = TCP)(HOST = dev)(PORT = 1527))
      (ADDRESS = (PROTOCOL = TCP)(HOST = dev)(PORT = 1521))

    )

Did a startup and there's a _single_ listener process that listens on both ports. I tested it. It works fine. Make sense as programming wise it's easy to bind to more than one port.

Peter, what I am unsure about is configuring for a different physical host as you have above. I assume that db2.domain is a different hardware plarform than db.domain?

In that case, I do not think it will work. Socket wise you use the bind() call to bind the port on an IP address (or multiple addresses if you use INADDR_ANY). That IP address must however exist _locally_ on the same system.

If the IP addresesses are in fact the same physical machine (i.e. multihome system), and host names for eth0 and eth1 (two network cards, each with its own IP stack), then it should work.

For example:

    (DESCRIPTION =

      (ADDRESS = (PROTOCOL = TCP)(HOST = dev)(PORT = 1527))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))

    )

In this case port 1521 can only be used for connections originating on the same system and using the loopback address.

Port 1527 will be available on the IP addresses for the machine (including 127.0.0.1).

You can also, instead of the local machine's host name, specify a specific IP address. In that case, the port should be bound by the listener to that IP only (unless the listener code also auto adds loopback to it).

> However in the Oracle Net Manager, I could not find a way to configure
> this configuration.

Er.. what is that? :-) (I never use the GUI tools myself - there's certain kind of satisfaction in vi'ing config files..)

--
Billy

Received on Tue Jun 10 2003 - 06:07:05 CDT