Re: "fallback_relay loop" revisited

From: Victor Duchovni (no email)
Date: Mon Jan 24 2005 - 13:32:27 EST

  • Next message: Wietse Venema: "Re: "fallback_relay loop" revisited"

    On Mon, Jan 24, 2005 at 03:21:23PM -0200, Ricardo Pardini wrote:

    > Hello,
    >
    > I'm running Postfix 2.1.4 and 2.1.5 (Debian sarge/sid) on two
    > different boxes that serve as backup MXs for many domains. The main MX
    > (also running Postfix 2.1.5) had port 25 recently firewalled by my ISP.
    > Since then I added port 2525 to the main MX, using master.cf, and used
    > transport_maps in the backup MX's to direct them to send mail via port
    > 2525. Both backup MX's also use fallback_relay, since they serve other
    > purposes (small LAN server).
    > This seems to cause a mail loop when even port 2525 is unreachable.
    > Postfix tries to deliver to port 2525 and fails; fallback_relay kicks in
    > and sends it to my ISP, which tries to deliver to the main MX, fails,
    > and tries the backup MX (from where the mail has just come), repeat,
    > repeat, until someone detects the loop and bounces.
    >
    >
    > backup MX servers main.cf:
    >
    > fallback_relay = smtp.myisp.example.com
    > transport_maps = hash:/etc/postfix/transport
    > relay_domains = /etc/postfix/backup_mx

    Don't use a fallback relay when sending mail to your relay_domains.

    master.cf:
        relay unix ... smtp
            -o fallback_relay=

    make sure that all domains for which you accept mail from strangers
    and then relay to remote machines use the "relay" transport.

    -- 
    	Viktor.
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  • Next message: Wietse Venema: "Re: "fallback_relay loop" revisited"





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