Little OT: Block Domain with Sendmail

[Quentin Campbell]

> -----Original Message-----
> From: Pat Hall [mailto:patrick at imptoy.com] 
> Sent: 07 May 2002 20:38
> To: MAILSCANNER at JISCMAIL.AC.UK
> Subject: Re: Little OT: Block Domain with Sendmail
> 
> 
> try
> 
> domain.com    DISCARD
> 
> or
> 
> domain.com    REJECT

The choice of which (REJECT or DISCARD) to use _IS_ important.

If you REJECT mail it will generate an error reply back to the sender.
If that address is invalid then you will find large queues building up
on your mail server with all the consequential effects that brings.
NEVER use REJECT when blocking against spam attacks or an attempt at
denial of service. 

If you DISCARD mail then it is simply dropped in the bin and that is the
end of it. The sender has no idea that it was binned and assumes it was
successfully delivered. You do not generate extra mail traffic with
error messages and you minimise resource use. 

Quentin