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Re: stupid SMTP rejection of spammers

2001-06-15 12:04:26

Hi, Keith

Keith Moore wrote:

Start by writing a paper about "BCP of SMTP operation".

(1) Don't block empty envelope from:
(2) Don't say ok to a recipient address if you are not 100% sure you can do
local delivery.
(3) ...

any others that folks want to contribute?

Yes, certainly. Like you, I noticed a substantial increase of the blocking of
empty envelope from addresses, which worried me.

Apart from that, I noticed during the last couple of months (doing postmaster
duties for a company) that more and more MX-listed systems are misconfigured and
reject mail with SMTP 5xx status responses telling that they won't relay for 

I can easily show a number of these rejections. The annoying thing is, that when
I try to send mail to postmaster(_at_)domain or postmaster(_at_)Mx-listed host, 
messages also are rejected with the same message.

So please ad:

(3) don't reject mail if you are listed as MX host
(4) always support postmaster(_at_)domain, for all domains for which you send 
mail to
the Internet.

BTW: I wouldn't name it a BCP, since most of the above items are clearly stated
as requirements in RFC's. So I would call it an informational RFC (or what's the
name for such an RFC?), like there is also an RFC stating common configuration
errors in DNS/Bind (I don't remember the RFC number, but I believe Piet 
CWI has contributed to it).