Postfix Help Required

Discussion in 'Server Operation' started by aadeusi, May 14, 2008.

  1. aadeusi

    aadeusi New Member

    Is there anyway Postfix can be configured to relay to a second/backup host in the event where the primary host is unavailable or down? I know that the 'relayhost' parameter only allows for single host relay, but I'm hoping there's a tweak or configuration change that can skirt that limitation.
    The use of external services e.g. BIND (DNS) and/or MX records is not an option in this case and neither is the use of a load-balancer.
    Therefore the configuration required has to be a function of Postfix itself.
    Please let me know if you have any thoughts or ideas that may help.
    Thank you.
  2. falko

    falko Super Moderator ISPConfig Developer

  3. aadeusi

    aadeusi New Member

    Hi Falko. Thanks for the response.
    What I actually was looking for was this:

    allback_relay (default: empty)

    Optional list of relay hosts for SMTP destinations that can't be found or that are unreachable. With Postfix 2.3 this parameter is renamed to smtp_fallback_relay.

    By default, mail is returned to the sender when a destination is not found, and delivery is deferred when a destination is unreachable.

    The fallback relays must be SMTP destinations. Specify a domain, host, host:port, [host]:port, [address] or [address]:port; the form [host] turns off MX lookups. If you specify multiple SMTP destinations, Postfix will try them in the specified order.

    Note: before Postfix 2.2, do not use the fallback_relay feature when relaying mail for a backup or primary MX domain. Mail would loop between the Postfix MX host and the fallback_relay host when the final destination is unavailable.

    * In specify "relay_transport = relay",
    * In specify "-o fallback_relay =" (i.e., empty) at the end of the relay entry.
    * In transport maps, specify "relay:nexthop..." as the right-hand side for backup or primary MX domain entries.

    Postfix version 2.2 and later will not use the fallback_relay feature for destinations that it is MX host for.

    However, thanks again!!!! :D

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