Bounce <-> Bounce <-> Bounce

Jan-Peter Koopmann Jan-Peter.Koopmann at SECEIDOS.DE
Mon Jun 28 09:56:40 IST 2004

On Sonntag, 27. Juni 2004 4:55 G. Armour Van Horn wrote:

Let me start over again: You said:

"send a 5.1.1 User Unknown" will get you a third message back... Who is
"sending" the 511? Your MTA? If your MTA is replying with 511 to
messaged sent to unknown users then you are ok since this is the desired
behaviour and will NOT result in additional messages. Technically this
is no bounce btw!

> Okay, what is a "catchall email alias" and where do I find them so I
> can remove them? 

Question: Is your MTA accepting mail for whatever at or just
for the local parts that actually exist? 

If it is accepting for every possible local part (thus never sending a
5xx user unknown) you must teach your MTA the valid local parts. How
this is done depends on your MTA. And even then several possibilities
remain: If you are using local users only it is easy. Otherwise you
could either use LDAP or create lists of valid local parts from your
Exchange/Notes/whatever-mail system automatically and push them to your
MailScanner box.

In many cases there is no "catchall email alias". Exchange (up to 2000)
always accepts mail for every local part, then scans the local part and
- if it does not exist - actively sends a non delivery report to the
sender which in case of spam mosty results in the third message you are
talking about. You can configure your MTA in such a way that valid local
parts are delivered correctly and all other e-mails are delivered to one
"spam-recipient". This would be the "catchall email alias" the guys were
talking about. This is hardly the case if you are using your MailScanner
box as a mail relay for Exchange/Notes/etc. only.

Therefore: Please tell us a bit more about your environment and we will
try to help.


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