On Tue, 16 Jun 2015 11:27:58 -0500, you wrote:>No attempt to deliver almost always means either: >- a DNS problem; the sender can't find the destination, or finds the >"wrong" destination.That would be interesting, since I tried both the actual IP address and the DNS name for the test node. Neither message got through.>- a connectivity problem; the sender can't connect to the >destination. Possibly a firewall not open.Now there's a possibility, but I am not aware of running any firewall on the remote machine.
> Date: Tuesday, June 16, 2015 01:13:47 PM -0400 > From: Steve Matzura <number6 at noisynotes.com> > > On Tue, 16 Jun 2015 11:27:58 -0500, you wrote: > >> No attempt to deliver almost always means either: >> - a DNS problem; the sender can't find the destination, or finds >> the "wrong" destination. > > That would be interesting, since I tried both the actual IP address > and the DNS name for the test node. Neither message got through. > >> - a connectivity problem; the sender can't connect to the >> destination. Possibly a firewall not open. > > Now there's a possibility, but I am not aware of running any > firewall on the remote machine.By default, most MTAs only listen to localhost, so don't accept externally derived mail. Try telnetting to port 25 on the machine from some place off your machine's network. If you get a "hang", it's likely a firewall issue. If you get a "connection refused" message it's probably that the MTA isn't listening on the external interface. If the MTA responds, do a manual delivery exchange and see what you get. If you're not seeing anything in your maillog, this is very likely an issue with your MTA's configuration, not dovecot.
On Tue, 16 Jun 2015 17:31:07 +0000, you wrote:>By default, most MTAs only listen to localhost, so don't accept >externally derived mail. Try telnetting to port 25 on the machine >from some place off your machine's network. If you get a "hang", >it's likely a firewall issue. If you get a "connection refused" >message it's probably that the MTA isn't listening on the external >interface. > >If the MTA responds, do a manual delivery exchange and see what you >get. > >If you're not seeing anything in your maillog, this is very likely >an issue with your MTA's configuration, not dovecot.Now that I think about and concentrate on what you wrote, make perfect sense. Add to that the fact that I received bounces from my ISP that all said the same thing: Unable to establish an SMTP connection. The return code was 4.5.1.