Disaster recovery recommendations for RH Linux 8.0...

[Tobias Speckbacher]

Edward,

Afaik the most commonly used smtp server implementations do support this
type of setup.  I agree its not required, but highly encouraged by the
authors of the rfc.

>From RFC 974 ( http://www.faqs.org/rfcs/rfc974.html ):

<lawyerly quoting>
"  If the list of MX RRs is not empty, the mailer should try to deliver
   the message to the MXs in order (lowest preference value tried
   first).  The mailer is required to attempt delivery to the lowest
   valued MX.  Implementors are encouraged to write mailers so that they
   try the MXs in order until one of the MXs accepts the message, or all
   the MXs have been tried.  A somewhat less demanding system, in which
   a fixed number of MXs is tried, is also reasonable.  Note that
   multiple MXs may have the same preference value.  In this case, all
   MXs at with a given value must be tried before any of a higher value
   are tried.  In addition, in the special case in which there are
   several MXs with the lowest preference value,  all of them should be
   tried before a message is deemed undeliverable."
</lawyerly quoting>


In any case, I would consider myself a negligent admin should I opt to
implement corporate mail infrastructure without having a backup mx host
(preferably in different locations).

-Tobias




-----Original Message-----
From: redhat-list-bounces at redhat.com
[mailto:redhat-list-bounces at redhat.com] On Behalf Of Edward J. Weinberg
Sent: Wednesday, April 28, 2004 4:56 AM
To: General Red Hat Linux discussion list
Subject: RE: Disaster recovery recommendations for RH Linux 8.0...

On Tue, 2004-04-27 at 14:15, Tobias Speckbacher wrote:

> The smtp protocol offers you to set backup mx records via dns.
> This will cause the sending server to try all of these before giving
up
> on delivery. (should the server in question be your MX host). Quick
> search yielded http://www.dyndns.org/support/kb/mxrecords.html on this
> topic.

Might do that.  You need to think like a lawyer.  The RFC says you CAN
try other MS records, not that your mail server MUST try them.  Some
mail servers do and some don't.

Your reference supports this:
"In addition to specifying the mail server which should receive mail for
a domain, MX records can also specify the host(s) to which mail can be
delivered if the primary mail server is off-line."

CAN be delivered is different from MUST be delivered.

That means that some email might be delivered to the secondary MX.

> I would definitely set up the system with 2 drives in a raid 1
> configuration.  If you can afford it go for hardware raid, otherwise
use
> the md feature in RH.
> 
> http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html
> 
> -Tobias
> 
> -----Original Message-----
> From: redhat-list-bounces at redhat.com
> [mailto:redhat-list-bounces at redhat.com] On Behalf Of Ed Wilts
> Sent: Tuesday, April 27, 2004 6:29 AM
> To: General Red Hat Linux discussion list
> Subject: Re: Disaster recovery recommendations for RH Linux 8.0...
> 
> On Tue, Apr 27, 2004 at 10:07:31AM -0400, Ken Morley wrote:
> > I have a RH Linux 8.0 server used to filter email for spam and
virues.
> It
> > receives email, filters it through SpamAssassin and ClamAV and then
> relays
> > the email to our Exchange server.  The email is only on the server
for
> a few
> > seconds.
> 
> This is what we do here.  The way we've solved it is to run 2 RHL
> servers and have DNS records that round-robin between them.  If either
> system fails, the other will take 100% of the load, but on average,
each
> system takes half the load.
> 
> > Can anyone recommend a simple, inexpensive solution that would allow
> me to
> > image the hard drive periodically and quickly restore to a
replacement
> hard
> > drive?  I'm thinking that the backup media would probably be CD-ROM
> (the
> > entire installation is only about 800MB uncompressed).
> 
> http://www.mondorescue.org
> 
> -- 
> Ed Wilts, Mounds View, MN, USA
> mailto:ewilts at ewilts.org
> Member #1, Red Hat Community Ambassador Program
> 
> 
> -- 
> redhat-list mailing list
> unsubscribe mailto:redhat-list-request at redhat.com?subject=unsubscribe
> https://www.redhat.com/mailman/listinfo/redhat-list
-- 
Edward J. Weinberg <edw at q5comm.com>


-- 
redhat-list mailing list
unsubscribe mailto:redhat-list-request at redhat.com?subject=unsubscribe
https://www.redhat.com/mailman/listinfo/redhat-list