Re: Two instances, two listeners and /etc/services

Ludo Joris wrote:
>
> A few weeks ago I created a second instance, recreated the
> tnsnames.ora, sqlnet.ora and listener.ora files with network
> manager (one listener on port 1526, the other on port 1527).
> I can now connect to both databases over the network.
> But I forgot to update my /etc/services file on the host
> machine.
> According to Oracle7 Server Installation Guide for HP 9000
> Series 700/800 Release 7.3, Prepare to install SQL*Net version 2
> products, Setup for the Oracle TCP/IP adapter, I added this
> line when installing Oracle7:
>
> listener 1526/tcp #SQL*Net version 2 listener port
>
> From Oracle7 Administrator's Reference for UNIX Release 7.3:
> "Oracle recommends that you reserve a port for your SQL*Net
> listener in the /etc/services file" and "Reserve more than one
> port to start more than one listener".
> So, I should add this line to /etc/services:
>
> listener2 1527/tcp #SQL*Net version 2 listener port
>
> The file /etc/services associates service names and aliases
> with the port number and protocol, says the man page.
>
> I do not understand why exactly I have to add these lines to
> /etc/services.
> What does Oracle mean by 'reserve a port'?
> Do I really need a line in the /etc/services file for every
> instance's listener to make it work?
>
> I have Oracle7 Server 7.3.2.3 on HP-UX 10.20.
>
> Thanks.
>
> --
> Ludo Joris
> RUCA - University of Antwerp, Belgium
> lujo_at_ruca.ua.ac.be

First off you don't need a listener for each instance. A single listener can support multiple instances.

The etc/services file serves as documentation of which ports (aka sockets) are being utilized to prevent collisions (note that some software products actually reference and drive off of this file but not oracle).

Ken F. Received on Mon Mar 03 1997 - 00:00:00 CST