[hobbit] Re: 554 SMTP synchronization error

[Dominique Frise]

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