[PLUG] Comcast Bouncing Outbound Mail

[Chris Jantzen]

On Sat, Jun 12, 2004 at 12:44:50AM -0700, Paul Johnson wrote:
> Don't just silently drop messages on the floor, either accept them or
> reject them or you run a very real risk of losing legitimate mail that
> matched the spam filter.

Plus, in theory, it's possible that spam senders might interpret the
reject message and update their lists. Maybe.

> Except you're not saving any bandwidth doing it that way, and you're
> potentially sacrificing the reliability of your server for legit senders
> to do it.

To spell it out even more clearly for Rich:

* If you bounce, your mail server constructs a message and delivers it
to the "From:" address.

* If you reject, you send a 500-series SMTP code and the remote server
is responsible for forming a bounce message for its users. Nothing
more happens.

* If you drop, you send a 250 SMTP code and the other side thinks it
delivered the email successfully. This has the deleterious side
effects for potentially good mail that Paul mentioned, in addition to
making spam servers think they've got a live one.

Notice how between dropping and rejecting you *maybe* save 10 bytes
*during* the SMTP session by dropping -- depending on the length of
your server's human readable messages. That's it. No further server
load or network traffic whatsoever.

-- 
chris kb7rnl =->
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.pdxlinux.org/pipermail/plug/attachments/20040612/e55c4753/attachment.asc>