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Re: [hobbit] Re: 554 SMTP synchronization error

Kolbjørn Barmen wrote: 
On Wed, 17 May 2006, Dominique Frise wrote:


Hi all,

Maybe this has been discussed already but I can't find any relevant info.
All our smtp tests sporadically report similar error:

------------
yellow  Wed May 17 14:37:21 2006 smtp NOT ok

Service smtp on mailc is not OK : Unexpected service response


554 SMTP synchronization error..

Seconds: 0.00
------------

How can we avoid this? 


I made my own SMTP-tester (to test MX for certain domains, not SMTP on
certain hosts) and there I met this problem. My test is as follows

MXTEST=$((sleep 1 ; echo quit) | nc -w 1 ${MXHOST} 25) || MXCOLOR="red"

Without the sleep, some microsoft servers refused to repond 220, and
without the -w 1 for netcat, some exim servers reponded with the above
554. (IIRC, it might have been the other way around)

I dont really understand why the sleep make any difference, but somehow it
does.


After looking deeper into this issue at our site, this error appears only when testing Exim 4.x mail transfer agent.

--------extract of Exim 4.30 doc------------
smtp_enforce_sync
Type:  boolean
Default:  true

The SMTP protocol specification requires the client to wait for a response from the server at certain points in the dialogue. Without PIPELINING these synchronization points are after every command; with PIPELINING they are fewer, but they still exist. Some spamming sites send out a complete set of SMTP commands without waiting for any response.
Exim protects against this by rejecting a message if the client has sent further input when it should not have. The error response “554 SMTP synchronization error” is sent, and the connection is dropped.
--------------------

The bbnet-test is to fast!

Would it be possible to integrate a -configurable in bb-services- timeout between the connexion established and the data sent by bbnet-test?


Dominique
UNIL - University of Lausanne