it's not so much a feature of the listener as it is of DNS as far as I
know. One of the reasons it's best not to hard-code IP addresses into
the listener.ora is because when you do a failover, or combine machines
as you have, the listener.ora and tnsnames.ora files need to be
updated.
If you use DNS and let the DNS server resolve the address, you don't
have to change anything.
This has been around for as long as I can remember using the listener,
which means going back to version 6
Rachel
- Djordje Jankovic <djankovic_at_corp.attcanada.ca> wrote:
> Something I learned today, but haven't seen it documented anywhere
> and would
> like to see whether anybody has come across it.
>
> We have a Sun server (call it oracle.acme.com). It came to life by
> combining two machines (oracle1.acme.com and oracle2.acme.com). So
> now it
> has two IP addresses: hme0: x.y.z.001 - from oracle1 and hme1:
> x.y.z.002 -
> from oracle2. There are few databases there (some of them were on
> oracle1
> some on oracle2) and one listener listening to all of them.
>
> If you configure listener.ora file so that HOST=x.y.z.001, or
> HOST=x.y.z.002
> that listener listens to that ONE IP only. However, if you put
> HOST=oracle.acme.com in listener.ora than it listens to all IPs (in
> netstat
> -an you see that it is listening to "*.1521" instead of to
> "oracle.acme.com.1521"). That would mean that oracle does not
> resolve DNS
> at replaces it with IP but first checks whether this is the primary
> IP for
> that box.
>
> So, once we have put HOST=oracle.acme.com, all the connections were
> OK
> (coming from clients with tnsnames files that are pointing to old
> oracle1.acme.com and oracle2.acme.com) Of course DNS was changed..
>
> Anybody has come across this undocumented feature ? Any explanation
> to that
> ?
>
> Djordje
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Djordje Jankovic
> INET: djankovic_at_corp.attcanada.ca
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing
> Lists
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--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Rachel Carmichael
INET: wisernet100_at_yahoo.com
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
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Received on Tue Dec 11 2001 - 11:05:55 CST
