Re: 550 5.1.1

  • From: Danny <nocmonkey@xxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Thu, 4 Nov 2004 09:34:42 -0500

On Thu, 4 Nov 2004 09:07:58 -0500, Stelley, Douglas <dstelley@xxxxxxx> wrote:
> Good morning, 
> I want to reduce the amount of NDR's I'm sending out and I may have to
> change the way I handle mail. 

Indeed. I do not like the way Microsoft handles email at the gateway.
The NDR should happen right during the intial SMTP conversation, not
moments later after conversation has completed.
> Right now mail comes in via 2 gateways sitting in the DMZ, they are
> processed for Spam/viruses using GFI & Mcafee products.

Do you have an old Pentium (whatever) computer not being used? If so,
email me off list and I would be glad to assist you setup a real SMTP
gateway server (for free) which would have a valid list of recipients.
If someone tries to send an email to
randominvalidaddress@xxxxxxxxxxxxxx, the senders MTA will be
responsible for the NDR, not your server because it will happen during
the intial SMTP conversation.

Personally, I prefer to avoid having Microsoft services accessible
from the Internet. Believe it or not we are a "Microsoft shop",
however, none are accessible from the Internet. The only OS responding
to services (SMTP for example) from the Internet, is FreeBSD.

> I would like to have the 550 5.1.1 filtering done on the gateways but can't
> quite figure it out.

I do not believe Microsoft's SMTP server supports this, although I
could be wrong.
> Using the LDAP Lookup tab did no good I believe because they are not
> members. 

Not only that, but do you want an LDAP lookup to happen every time a
valid and invalid email is sent to your servers? DoS comes to mind.


Other related posts: