serialmail suddenly stops working

Hi all:

	I have a customer with a qmail server, and I receive and queue his mail 
(and eventually send it to him) using the system described in the 
AUTOTURN document. It has been working great until today, when it 
suddenly stopped working. The symptoms are:

	1) The cron job on my end which fires up serialmail to send him the 
mail times out with "serialsmtp: fatal: network read error: timed out".
	2) Executing by hand the command returns the same error.
	3) Telnetting to port 25 of the customer's mail server and typing mail 
by hand *does work*.
	4) The customer tells me that he sees an incoming SMTP connection 
starting up in his qmail server when my serialmail fires up.
	5) Using tcpdump I can see that, whenever serialmail starts a SMTP 
connection with the client's server, there comes a point where it keeps 
sending the same packet (according to the data sequence numbers), 
without making further progress.


	What's happening?



					Paulo Jan.
					DDnet.