[Mimedefang] Specifying valid users?

[Josh Graham]

Thanks guys, I've been working with the Exchange 2003 version but
md_check_against_smtp_server doesn't log anything so I can't tell why
it's not working at the moment.  Also, I don't bounce any invalid users
at the exchange server because I've got them redirected to a special
mailbox.  No worries there.




JOSH GRAHAM

Lead MIS|IT Engineer

TRANXITION

3700 SW Murray Boulevard | Suite 200

Beaverton, OR 97005

503.291.6413

503.641.4668 (fax)


-----Original Message-----
From: mimedefang-bounces at lists.roaringpenguin.com
[mailto:mimedefang-bounces at lists.roaringpenguin.com] On Behalf Of Kevin
A. McGrail
Sent: Wednesday, August 10, 2005 12:36 PM
To: mimedefang at lists.roaringpenguin.com
Subject: Re: [Mimedefang] Specifying valid users?

I hesitate to answer this fully because I think the archives must be
chock-full of answers to this question but I will give you the following
pointers just because you seem a little out of your depth:

The spam pattern you are seeing is most likely what is called a
dictionary attack.  Blocking these at the gateway is essential for any
company as the bounces created by these attacks are as bad as the
attacks themselves in many cases where they forge the from address.

For exchange 2003, see
http://www.peregrinehw.com/downloads/ldap/NOTE-EXCHANGE2003 and setup a
recipient filter using  md_check_against_smtp_server.

For exchange 2000, setup an LDAP link for sendmail.  I use this
solution: 
http://www.peregrinehw.com/downloads/ldap/INSTALL

Regards,
KAM

> Hi all, I've noticed that lately a lot of spam is directed to people 
> that don't actually exist in my company.  It looks like spammers are 
> just guessing names of people who might work here.  Since my Linux box

> is just a relay for the exchange server I don't know of anyway to 
> actually do checking to see if a user exists.  Also, since anything 
> labeled as spam gets redirected to a specific mailbox it doesn't even 
> get rejected at the exchange server.

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