On Fri, Jan 12, 2001 at 02:47:26AM +0100, Markus Stumpf wrote:
> I am going to patch qmail-smtpd to have a maximum number of rcpt to's
> it will accept in one session. (I regularily see spammers that try
> to send to a lot of (valid) adresses in one bulk).
> The value I am thinking of is around 20 and after that I will reject
> the recipients with a "451 Too many recipients." message.
>
> Looking at RFC821 I find (Page 42)
> recipients buffer
> The maximum total number of recipients that must be
> buffered is 100 recipients.
>
> Thus this patch would violate RFC821. Do you think this violation is
> critical? A correctly implemented smtp server should resend those
> "451 ack'd" addresses anyways, shouldn't it?
With the operative word being "correctly". MTAs may be better but my
experience is that most clients don't do it properly so if your SMTP
server is used by local clients, such as Eudora, then large recipient
mails will fail.
> Hmmm ... thinking about that quote (maybe it's my bad english) does that
> make a sense at all? What's the meaning? Wouldn't
> The MINIMUM total number of recipients that must be
> buffered is 100 recipients.
> make more sense if one would like to impose a limit?
> And why (some lines later at that page) would one reject too many
> recipients with a "552 Too many recipients.", i.e. a permanent failure
> code instead of a 4xx temporary code?
>
> Puzzled,
Like numerous things in that standard, they look confusing from
today's perspective.
Regards.
