debugging SMTP AUTH

I have postfix 2.3.3 installed and configured on a home machine
(running debian etch, if it matters). Since I have a dynamic IP, I'm
using the sender-dependent relay host and authentication features to
relay my mail out through one of two servers on which I have accounts.
Of the two, one works fine, while the other consistently gives me
"relay access denied" bounce messages, which I assume means I'm not
authenticating properly with it. How can I find out if the smtp client
is attempting to authenticate and, if so, why it isn't succeeding? All
the logs and reports I've looked at merely have the failure message
itself, not the previous history. I've tried using sendmail -v and
debug_peer_list, perhaps incorrectly.

Example error message:

Sep 21 20:07:06 spip postfix/smtp[20508]: C23893A626: to=<XXX@mit.edu>,
relay=in1.smtp.messagingengine.com[66.111.4.73]:25, delay=0.89,
delays=0.03/0.03/0.32/0.51, dsn=5.0.0, status=bounced (host
in1.smtp.messagingengine.com[66.111.4.7
3] said: 554 <XXX@mit.edu>: Relay access denied (in reply to RCPT TO
command))

To add insult to injury, it was working last week, and I can't figure
out what relevant change I might have made.

Any guidance would be much appreciated.

Ian

ian_leroux@fastmail.fm wrote:
> I have postfix 2.3.3 installed and configured on a home machine
> (running debian etch, if it matters). Since I have a dynamic IP, I'm
> using the sender-dependent relay host and authentication features to
> relay my mail out through one of two servers on which I have accounts.
> Of the two, one works fine, while the other consistently gives me
> "relay access denied" bounce messages, which I assume means I'm not
> authenticating properly with it. How can I find out if the smtp client
> is attempting to authenticate and, if so, why it isn't succeeding? All
> the logs and reports I've looked at merely have the failure message
> itself, not the previous history. I've tried using sendmail -v and
> debug_peer_list, perhaps incorrectly.
>
> Example error message:
>
> Sep 21 20:07:06 spip postfix/smtp[20508]: C23893A626: to=<XXX@mit.edu>,
> relay=in1.smtp.messagingengine.com[66.111.4.73]:25, delay=0.89,
> delays=0.03/0.03/0.32/0.51, dsn=5.0.0, status=bounced (host
> in1.smtp.messagingengine.com[66.111.4.7
> 3] said: 554 <XXX@mit.edu>: Relay access denied (in reply to RCPT TO
> command))
>
> To add insult to injury, it was working last week, and I can't figure
> out what relevant change I might have made.
>
> Any guidance would be much appreciated.
>
> Ian


The server that you are connecting to doesn't support SMTP AUTH.
There are no AUTH mechanism being advertised, as shown below:


# telnet 66.111.4.73 25
Trying 66.111.4.73...
Connected to 66.111.4.73.
Escape character is '^]'.
220 mx4.messagingengine.com ESMTP . No UCE permitted.
ehlo hippie.cincomail.com
250-mx4.messagingengine.com
250-PIPELINING
250-SIZE 71000000
250-ETRN
250 8BITMIME


--
Greg

Greg Hackney wrote:
> ian_leroux@fastmail.fm wrote:
> > I have postfix 2.3.3 installed and configured on a home machine
> > (running debian etch, if it matters). Since I have a dynamic IP, I'm
> > using the sender-dependent relay host and authentication features to
> > relay my mail out through one of two servers on which I have accounts.
> > Of the two, one works fine, while the other consistently gives me
> > "relay access denied" bounce messages, which I assume means I'm not
> > authenticating properly with it. How can I find out if the smtp client
> > is attempting to authenticate and, if so, why it isn't succeeding? All
> > the logs and reports I've looked at merely have the failure message
> > itself, not the previous history. I've tried using sendmail -v and
> > debug_peer_list, perhaps incorrectly.
> >
> > Example error message:
> >
> > Sep 21 20:07:06 spip postfix/smtp[20508]: C23893A626: to=<XXX@mit.edu>,
> > relay=in1.smtp.messagingengine.com[66.111.4.73]:25, delay=0.89,
> > delays=0.03/0.03/0.32/0.51, dsn=5.0.0, status=bounced (host
> > in1.smtp.messagingengine.com[66.111.4.7
> > 3] said: 554 <XXX@mit.edu>: Relay access denied (in reply to RCPT TO
> > command))
> >
> > To add insult to injury, it was working last week, and I can't figure
> > out what relevant change I might have made.
> >
> > Any guidance would be much appreciated.
> >
> > Ian
>
>
> The server that you are connecting to doesn't support SMTP AUTH.
> There are no AUTH mechanism being advertised, as shown below:
>
>
> # telnet 66.111.4.73 25
> Trying 66.111.4.73...
> Connected to 66.111.4.73.
> Escape character is '^]'.
> 220 mx4.messagingengine.com ESMTP . No UCE permitted.
> ehlo hippie.cincomail.com
> 250-mx4.messagingengine.com
> 250-PIPELINING
> 250-SIZE 71000000
> 250-ETRN
> 250 8BITMIME

Thank you very much. That pin-pointed the problem for me: I'd enabled
MX lookups by removing the square brackets around the hosts in the
sender-dependent relayhosts map, so that I was trying to authenticate
with the wrong server for outbound traffic.

Thanks again for the assistance,

Ian