On Mon, Sep 28, 2009 at 11:00:15AM -0500, Noel Jones wrote: >> After searching online and reading a lot it seemed to me that, assuming >> that the company?s SMTP server is 100.100.100.100 (for one reason or >> another we use the IP address rather than FQDN) and the 3G operator?s >> SMTP server is smtp.3g.com, what I needed was this in the Postfix >> configuration: >> >> relayhost = 192.0.2.1
Change that to include the required "[]" around the bare IP: relayhost = [192.0.2.1] >> smtp_fallback_relay = smtp.3g.com Fine. >> The idea being that when the link to 100.100.100.100 is down (as in that >> network connection is down) the machine failsover its network >> connectivity to the 3G one and uses smtp.3g.com. > > Postfix will always attempt to connect to $relayhost, correct. > and will only use > smtp_fallback_relay if it can't connect to the relayhost at all. No, Postfix (from 2.1 and later IIRC) will also use the fallback relay after a 4XX failure in a delivery attempt via the primary nexthop, unless the current host is a back-up MX for the destination domain. > If postfix is able to connect to 100.100.100.100 via the 3G connection, the > fallback settings will never be used - even if the actual mail transfer > fails. This is not accurate. > If you need more help, please show "postconf -n" output and logging > demonstrating the problem. Logging would be very useful. -- Viktor. Disclaimer: off-list followups get on-list replies or get ignored. Please do not ignore the "Reply-To" header. To unsubscribe from the postfix-users list, visit http://www.postfix.org/lists.html or click the link below: <mailto:majord...@postfix.org?body=unsubscribe%20postfix-users> If my response solves your problem, the best way to thank me is to not send an "it worked, thanks" follow-up. If you must respond, please put "It worked, thanks" in the "Subject" so I can delete these quickly.