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RE: Listeners listening to multiple IPs

From: Djordje Jankovic <djankovic_at_corp.attcanada.ca>
Date: Tue, 11 Dec 2001 10:29:46 -0800
Message-ID: <F001.003DA1F4.20011211101125@fatcity.com>

I am not talking whether putting DNS entry works, but am just pointing to the fact that oracle behaves differently if you put hardcoded IP - it than listens to one IP only, and if you put the dns name - listens to all IPs.

Djordje

> -----Original Message-----
> From: Rachel Carmichael [mailto:wisernet100_at_yahoo.com]
> Sent: Tuesday, December 11, 2001 11:50 AM
> To: Multiple recipients of list ORACLE-L
> Subject: Re: Listeners listening to multiple IPs
>
>
> 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
> --------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
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-- 
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
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).
Received on Tue Dec 11 2001 - 12:29:46 CST

Original text of this message

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