Weird Problem with MailScanner

[Damian Rivas]

Paul Houselander: I forgot to answer you your question, yes there are
lots of underivable messages, but they are not the most, the biggest
portion of mails stuck are spam, however underivable messages are a
considerable number and perhaps you are probably right and the server is
under a backscatter attack. I'll check the documentation you sent me.
There is no doubt, I'll have to implement a recipient checking at smtp
level(as Jason has advised me).
 
 
<http://www.cht.com.ar/> 
-----Mensaje original-----
De: mailscanner-bounces at lists.mailscanner.info
[mailto:mailscanner-bounces at lists.mailscanner.info] En nombre de Paul
Houselander
Enviado el: viernes, 19 de octubre de 2007 13:52
Para: MailScanner discussion
Asunto: RE: Weird Problem with MailScanner



	Were lots of the messages undeliverable messages?
	 
	In which case it could be your domain was under a backscatter
attack see - http://spamlinks.net/prevent-secure-backscatter.htm
	 
	Ive had this happen to various customers where all of a sudden
there incommg e-mail shoots up to ridiculous levels.
	 
	The quickest form of defence would be to implement some sort of
recipient verification - I use mimedefang to achieve this here
(sendmail). Before sendmail accepts the e-mail it checks if the
recipient is indeed a valid user on your exchange box.
	 
	You need to be running at least Exchange 2003 and above and
enable recipient filtering http://support.microsoft.com/kb/886208
	 
	If the messages were not lots of undeliverable messages and all
to valid recipients I would agree with the other reply that your server
sounds like it needs an upgrade to cope.
	 
	Cheers
	 
	Paul
	 

		-----Original Message-----
		From: mailscanner-bounces at lists.mailscanner.info
[mailto:mailscanner-bounces at lists.mailscanner.info]On Behalf Of Gareth
		Sent: 19 October 2007 17:32
		To: MailScanner discussion
		Subject: RE: Weird Problem with MailScanner {Scanned by
Allteks Mailsafe}
		
		
		I would say it is seriously in need of a memory upgrade.
The minimum recomendation is 1GB.

			-----Original Message-----
			From: mailscanner-bounces at lists.mailscanner.info
[mailto:mailscanner-bounces at lists.mailscanner.info]On Behalf Of Damian
Rivas
			Sent: 19 October 2007 17:22
			To: mailscanner at lists.mailscanner.info
			Subject: Weird Problem with MailScanner
			
			
			Hi there, I'm having a really weird problem and
as I am a n00b it gets a bit more difficult to find a solution. 
			 
			I'll explain the details first:
			 
			Since 6 months ago, I am the System
Administrator of a Tourism Agency. We use an E-mail Scanner in a server
with the following characteristics:
			 
			Processor: Pentium II 233 Mhz.
			RAM: 128 MB
			OS: Linux Slackware 9
			MailScanner version: 4.55.10
			 
			This E-mail Scanner use the MailScanner with
Sophos Antivirus and Spam Assasin to filter spam and scan incoming and
outcoming mails for viruses which are then redirected to an internal MS
Exchange Server or to the Internet, respectively by sendmail.
			 
			One month ago, the server started behaving
erratically. Instead of checking and sending mails as it normally did,
it started queueing mails massively and therefore accumulating great
quantities of them, it got up to 10000 mails queued up in a single day,
therefore, no one recieved a single mail. After many pointless attempts
to repair this problem and seeing that the Travel Agents were getting a
bit mad, I decided to redirect the MX server of our domains in the DNS
to the firewall, so that our E-Mail Scanner server didn't recieve more
mail, which was only going to contribute to making the problem worse,
more incoming mails, more queued mails.
			 
			With this, the server started sending the queued
mails and mail traffic was restored with the difference that mails
weren't scanned at all(they were no longer passing through the
MailScanner Server). When the mail queues were empty again, I tried to
reestablish the scanning service, but the problem appeared again.
			 
			I don't have a clear idea of what can be causing
this problem. The machine is pretty old, but the former administrator
told me that it had never had problems. I think that perhaps we are
being Spam Bombed and perhaps the System poor processing capabilities
cannot resists the increasing traffic and therefore it gets stuck and
keeps enqueueing mails.
			 
			Please if anyone can guide me I'll appreciate
it,
			Sorry if my English is a bit rusty, it is not my
native language, therefore if you need me to be more clear or try to
give more details of something, don't hesitate to ask so.
			Thanks in advance!
			
			<http://www.cht.com.ar/> 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.mailscanner.info/pipermail/mailscanner/attachments/20071022/2cf0131a/attachment.html