strange bounces

strange bounces

[James E Wilson]

Since no one seems to know what the problem is, I tried looking for
info, and found an interesting thread on the nntp.perl.org server in the
perl.qsmtpd mailing list, with the subject line "Strange bounce problem"
sent on Nov 4, 2004.  Since there is no convenient URL, I've quoted the
interesting parts of the most interesting message:

I don't know if this might help, but I just spent hours with ethereal
and
full debugging on all the servers and here is what is happening:

telnet server 25
220 server ESMTP qpsmtpd 0.28 ready; send us your mail, but not your spam.
503 MAIL before RCPT
503 MAIL FIRST

Now, looking at the tcpdumps reveals that you in fact never sent anything,
however, if you look at the logs you see that the server was dispatching
something like : RCTP TO: <thisuser@thisdomain.com>, back to ethereal and
you can see that sure enough a server sent that packet a good 10-15
seconds ago but was denied with the require_resolvable_fromhost.  What
seems like is happening is that Qpsmtpd is dropping the connection but the
buffers aren't being flushed so that when the next Qpsmtpd picks up the
file handle the old one had it's getting the data that was left over. 
I am running Pperl with --no-cleanup but enabling cleanup did nothing to
solve the problem as did just calling qpsmtpd directly from tcpserver
without pperl.  The only thing I have found that got rid of the problem
was to edit the require_resolvable_fromhost plugin and change it from
DENYHARD to DENYSOFT.  Hope this helps somebody out there.

Ed McLain

End quote.

There are also some other related suggestions in other messages in the
thread, but this one seemed like the most useful.  You might want to look at
the entire thread.
-- 
Jim Wilson, GNU Tools Support, http://www.specifix.com

Re: strange bounces

[Christopher Faylor]

On Thu, Nov 17, 2005 at 05:46:58PM -0800, James E Wilson wrote:
>Since no one seems to know what the problem is, I tried looking for
>info, and found an interesting thread on the nntp.perl.org server in the
>perl.qsmtpd mailing list, with the subject line "Strange bounce problem"
>sent on Nov 4, 2004.  Since there is no convenient URL, I've quoted the
>interesting parts of the most interesting message:

Actually, while I don't know precisely what the problem is, I have done
some googling as well.  I've been attempting to rally some support in
irc for testing a new version of qpsmtpd that is running on port 174 on
the system but, it seems like I'm the only person using it.  I've
verified that there are some code changes around the place where the
error is coming from so I'm hoping that things will at least be
different, if not improved.

We don't use require_resolvable_fromhost.  I don't think it's appropriate
to put that restriction on a site which is expected to service traffic
from a diverse community.

I'll probably switch over to the newest version of qpsmtpd sometime in the
next couple of days.

cgf

Re: strange bounces

[Daniel Jacobowitz]

On Thu, Nov 17, 2005 at 08:58:16PM -0500, Christopher Faylor wrote:
> Actually, while I don't know precisely what the problem is, I have done
> some googling as well.  I've been attempting to rally some support in
> irc for testing a new version of qpsmtpd that is running on port 174 on
> the system but, it seems like I'm the only person using it.  I've
> verified that there are some code changes around the place where the
> error is coming from so I'm hoping that things will at least be
> different, if not improved.

FWIW, I've gone back to testing it.  Here's the exim bits...


#################################
# This transport is used for delivering messages over SMTP connections.
remote_smtp_174:
  debug_print = "T: remote_smtp_174 for $local_part@$domain"
  driver = smtp
  port = 174

# deliver mail directly to the recipient. This router is only reached
# for domains that we do not relay for. Since we most probably can't
# have broken MX records pointing to site local or link local IP
# addresses fixed, we ignore target hosts pointing to these addresses.

dnslookup_174:
  debug_print = "R: dnslookup for $local_part@$domain"
  driver = dnslookup
  domains = sourceware.org : gcc.gnu.org : sources.redhat.com
  transport = remote_smtp_174
  same_domain_copy_routing = yes
  # ignore private rfc1918 and APIPA addresses
  ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8 : 192.168.0.0/16 :\
                        172.16.0.0/12 : 10.0.0.0/8 : 169.254.0.0/16 :\
			255.255.255.255
  no_more



-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: strange bounces

[Christopher Faylor]

On Thu, Nov 17, 2005 at 09:05:45PM -0500, Daniel Jacobowitz wrote:
>On Thu, Nov 17, 2005 at 08:58:16PM -0500, Christopher Faylor wrote:
>> Actually, while I don't know precisely what the problem is, I have done
>> some googling as well.  I've been attempting to rally some support in
>> irc for testing a new version of qpsmtpd that is running on port 174 on
>> the system but, it seems like I'm the only person using it.  I've
>> verified that there are some code changes around the place where the
>> error is coming from so I'm hoping that things will at least be
>> different, if not improved.
>
>FWIW, I've gone back to testing it.  Here's the exim bits...

Btw, I also added more debugging output so if you see the error again,
you should see what the failing command actually is.

Thanks for testing this.

cgf