incoming message lost

hi all,
I'm running exim 4.60 without problems for months.
In the last month I have a seriuos problems.
Message incoming from some domains get totally losted without any error sent
back to sender.
Exim is installed with Spamassassin and MailScanner

In the debug I get:
14614 SMTP>> 421 mail.XXXXXXXXXXX.it lost input connection^M
14614 LOG: smtp_connection MAIN
14614   SMTP connection from cp-out4.libero.it [212.52.84.104] lost
14614 search_tidyup called

thanks
--
Francesco Pasqualini
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Re: incoming message lost

It seems the error is at SMTP level (libero.it is the sender domain) so I
propend to exclude SpamAssasin and MailScanner.
I suspect it' is a problem related to network/firewall or to exim

thanks

On Mon, Sep 1, 2008 at 3:27 PM, Francesco Pasqualini <frapas <at> gmail.com>wrote:

> hi all,
> I'm running exim 4.60 without problems for months.
> In the last month I have a seriuos problems.
> Message incoming from some domains get totally losted without any error
> sent back to sender.
> Exim is installed with Spamassassin and MailScanner
>
> In the debug I get:
> 14614 SMTP>> 421 mail.XXXXXXXXXXX.it lost input connection^M
> 14614 LOG: smtp_connection MAIN
> 14614   SMTP connection from cp-out4.libero.it [212.52.84.104] lost
> 14614 search_tidyup called
>
> thanks
> --
> Francesco Pasqualini
>
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Re: incoming message lost

Here is the complete debug log, tanks:

14614 sender_fullhost = [212.52.84.104]
14614 sender_rcvhost = [212.52.84.104]
14614 Process 14614 is handling incoming connection from [212.52.84.104]
14614 host in host_lookup? yes (matched "*")
14614 looking up host name for 212.52.84.104
14614 DNS lookup of 104.84.52.212.in-addr.arpa (PTR) succeeded
14614 IP address lookup yielded cp-out4.libero.it
14614 gethostbyname2(af=inet6) returned 4 (NO_DATA)
14614 gethostbyname2 looked up these IP addresses:
14614   name=cp-out4.libero.it address=212.52.84.104
14614 checking addresses for cp-out4.libero.it
14614   212.52.84.104 OK
14614 sender_fullhost = cp-out4.libero.it [212.52.84.104]
14614 sender_rcvhost = cp-out4.libero.it ([212.52.84.104])
14614 set_process_info: 14614 handling incoming connection from
cp-out4.libero.it [212.52.84.104]
14614 host in host_reject_connection? no (option unset)
14614 host in sender_unqualified_hosts? no (option unset)
14614 host in recipient_unqualified_hosts? no (option unset)
14614 host in helo_verify_hosts? no (option unset)
14614 host in helo_try_verify_hosts? no (option unset)
14614 host in helo_accept_junk_hosts? no (option unset)
14614 SMTP>> 220 mail.XXXXXXX.it ESMTP Exim 4.60 Mon, 01 Sep 2008 14:44:01
+0200
14614 Process 14614 is ready for new message
14614 smtp_setup_msg entered
14614 SMTP>> 421 mail.XXXXXXX.it lost input connection
14614 LOG: smtp_connection MAIN

Re: incoming message lost

>14614 SMTP>> 220 mail.XXXXXXX.it ESMTP Exim 4.60 Mon, 01 Sep 2008 14:44:01
+0200
>14614 Process 14614 is ready for new message
>14614 smtp_setup_msg entered
>14614 SMTP>> 421 mail.XXXXXXX.it lost input connection
>14614 LOG: smtp_connection MAIN
>14614   SMTP connection from cp-out4.libero.it [212.52.84.104] lost

Is there a IPSEC VPN in between. As this might also be a symptom of failed
path MTU discovery. Where your machine wants 1500 byte TCP/IP-packets, but
because of failed detection (probably ICMP packet filtering) sender cannot
send big packets and those get dropped by network.

Additional test could be dropping MTU to 1400 bytes and see what happens.

More info (no need to cut&paste here):
http://en.wikipedia.org/wiki/Maximum_transmission_unit
"Path MTU discovery"

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Re: incoming message lost

Francesco Pasqualini wrote:
> Here is the complete debug log, tanks:
> 
> 14614 sender_fullhost = [212.52.84.104]
> 14614 sender_rcvhost = [212.52.84.104]
> 14614 Process 14614 is handling incoming connection from [212.52.84.104]
> 14614 host in host_lookup? yes (matched "*")
> 14614 looking up host name for 212.52.84.104
> 14614 DNS lookup of 104.84.52.212.in-addr.arpa (PTR) succeeded
> 14614 IP address lookup yielded cp-out4.libero.it
> 14614 gethostbyname2(af=inet6) returned 4 (NO_DATA)
> 14614 gethostbyname2 looked up these IP addresses:
> 14614   name=cp-out4.libero.it address=212.52.84.104
> 14614 checking addresses for cp-out4.libero.it
> 14614   212.52.84.104 OK
> 14614 sender_fullhost = cp-out4.libero.it [212.52.84.104]
> 14614 sender_rcvhost = cp-out4.libero.it ([212.52.84.104])
> 14614 set_process_info: 14614 handling incoming connection from
> cp-out4.libero.it [212.52.84.104]
> 14614 host in host_reject_connection? no (option unset)
> 14614 host in sender_unqualified_hosts? no (option unset)
> 14614 host in recipient_unqualified_hosts? no (option unset)
> 14614 host in helo_verify_hosts? no (option unset)
> 14614 host in helo_try_verify_hosts? no (option unset)
> 14614 host in helo_accept_junk_hosts? no (option unset)
> 14614 SMTP>> 220 mail.XXXXXXX.it ESMTP Exim 4.60 Mon, 01 Sep 2008 14:44:01
> +0200
> 14614 Process 14614 is ready for new message
> 14614 smtp_setup_msg entered
> 14614 SMTP>> 421 mail.XXXXXXX.it lost input connection

Re: incoming message lost

Yes you are right, may be the message are queued in the sender mailserver,
that will retry in the future....
but the problem remain... every attempt to send mail from some domains get
lost connection problem...

> No message was ever received to be lost, as the sending side never made
> it past the initial connection. Spambots and some really crappy old mail
> servers do this. Any decent mail server will try again.
>
> Generally, not something to worry about.
>
> --
> The Exim Manual
> http://www.exim.org/docs.html
> http://docs.exim.org/current/
>
> --
> ## List details at http://lists.exim.org/mailman/listinfo/exim-users
> ## Exim details at http://www.exim.org/
> ## Please use the Wiki with this list - http://wiki.exim.org/
>
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Re: incoming message lost

Probem "solved".
I reactivated the secondary/backup MX ( Exim version 4.50  ) server and now
the messages are arriving without problems trough the secondary MX.
May be there are some strange network problems between some net or some
problems with exim6.0.

We are in Italy, the secondary MX is in the USA.
So the messages now make bigger travel but without problems.

I remain in doubt about a possible exim problem.
The main SMTP is Exim version 4.60

thanks

On Mon, Sep 1, 2008 at 4:39 PM, Ted Cooper <eximX1211 <at> linuxwan.net> wrote:

> Francesco Pasqualini wrote:
> > Here is the complete debug log, tanks:
> >
> > 14614 sender_fullhost = [212.52.84.104]
> > 14614 sender_rcvhost = [212.52.84.104]
> > 14614 Process 14614 is handling incoming connection from [212.52.84.104]
> > 14614 host in host_lookup? yes (matched "*")
> > 14614 looking up host name for 212.52.84.104
> > 14614 DNS lookup of 104.84.52.212.in-addr.arpa (PTR) succeeded
> > 14614 IP address lookup yielded cp-out4.libero.it
> > 14614 gethostbyname2(af=inet6) returned 4 (NO_DATA)
> > 14614 gethostbyname2 looked up these IP addresses:
> > 14614   name=cp-out4.libero.it address=212.52.84.104
> > 14614 checking addresses for cp-out4.libero.it

Re: incoming message lost

> -----Original Message-----
> From: exim-users-bounces <at> exim.org 
> [mailto:exim-users-bounces <at> exim.org] On Behalf Of Francesco Pasqualini
> Sent: Mon 01 September 2008 15:47
> To: exim-users <at> exim.org
> Subject: Re: [exim] incoming message lost
> 
> Yes you are right, may be the message are queued in the 
> sender mailserver,
> that will retry in the future....
> but the problem remain... every attempt to send mail from 
> some domains get
> lost connection problem...
> 
> 
> > No message was ever received to be lost, as the sending 
> side never made
> > it past the initial connection. Spambots and some really 
> crappy old mail
> > servers do this. Any decent mail server will try again.
> >
> > Generally, not something to worry about.

Do you have an application-level firewall between the Internet and your
mail server?  If you do have, it may be deciding not to allow the
connection to continue because of rules of its own.

Check with your networking people to find out what is between your mail
server and your Internet link.

Re: incoming message lost

Hi !
I'm the networking pepole. 
The exim server is on DMZ, the tcp/ip ports needed to comunicate smtp are
open.
In fact we receive emails from many domains but not from some domains.

I didn't setup any firewall rules to stop establised connections to
continue.
I can double check this, but I'm quite shure.

Moreover absolutely no special rule is on the firewall about the connections
from/to the backup MX server, but from there the email are arriving with no
problems.

thnaks a lot for the help

Francesco Pasqualini

On Mon, Sep 1, 2008 at 6:18 PM, Chambers, Phil <P.A.Chambers <at> exeter.ac.uk>wrote:

>
>
>
> Do you have an application-level firewall between the Internet and your
> mail server?  If you do have, it may be deciding not to allow the
> connection to continue because of rules of its own.
>
> Check with your networking people to find out what is between your mail
> server and your Internet link.
>

Re: incoming message lost

On Mon, 1 Sep 2008, Francesco Pasqualini wrote:
>
> Hi !
> I'm the networking pepole. 

Look at path mtu as mentioned earlier.

Sniff the connection to get more clues as to what
is happening.

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Have you hugged your firewall today?   No spam, thanks.
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