BACKSCATTERER temporally blacklisted even if my server return error 550 on unknown recipient

[Charly]

Hi,

My SMTP server is blacklisted on backscatterer.org, that means I
accept unknown recipient. But it is not the case. My server return
"550 5.1.1 <***@mail.com>: Recipient address rejected: User unknown
in virtual mailbox table".

I declared reverse DNS and SPF. My server is not an open relay. It
uses greylists, blacklists, sender and recipient restrictions ... What
could be the problem ?

Thank's in advance

Regards

[Shmuel (Seymour J.) Metz]

In <4956fba4-8463-4876-a841-***@g23g2000yqh.googlegroups.com>, on
10/28/2009

My SMTP server is blacklisted on backscatterer.org, that means I accept
unknown recipient.

No, it means that you send a DSN, which could be, e.g., out of space.
Unknown recipient is just one of several problems, albeit the most common
and the easiest to deal with.

But it is not the case. My server return
virtual mailbox table".

Do you mean that your respond to, e.g., RCPT, with that text, or that you
send that text in an e-mail?

What could be the problem ?

Have you searched your logs? Do you have a cached list of valid mailboxes
that could get out of synch? If you use an external server, e.g., LDAP, to
validate mailboxes, what happens if the link to that server is congested
or down? Do you have a secondary MX that could be out of synch?
--
Shmuel (Seymour J.) Metz, truly insane Spews puppet
<http://patriot.net/~shmuel>

I reserve the right to publicly post or ridicule any abusive
E-mail. Reply to domain Patriot dot net user shmuel+news to contact
me. Do not reply to ***@library.lspace.org

[Charly]

On 29 oct, 16:19, "Shmuel (Seymour J.) Metz"

Post by Shmuel (Seymour J.) Metz
10/28/2009

My SMTP server is blacklisted on backscatterer.org, that means I accept
unknown recipient.

No, it means that you send a DSN, which could be, e.g., out of space.
Unknown recipient is just one of several problems, albeit the most common
and the easiest to deal with.

But it is not the case. My server return
virtual mailbox table".

Do you mean that your respond to, e.g., RCPT, with that text, or that you
send that text in an e-mail?

It's the DSN returned by text during SMTP session. I confirmed with
emulating smtp session by telnet.

Post by Shmuel (Seymour J.) Metz

What could be the problem ?

Have you searched your logs? Do you have a cached list of valid mailboxes
that could get out of synch? If you use an external server, e.g., LDAP, to
validate mailboxes, what happens if the link to that server is congested
or down? Do you have a secondary MX that could be out of synch?

According to history, the logs expired. I use SQL database as external
server. There is no cache list. If SQL server fails, a timeout occurs
after the RCTP.
My secondary MX also points to the same mail server.

Today, my primary MX is no more listed due to expiration. I figure out
that BACKSCATTERER is going to check again my server during next
days. I will check the log.

Post by Shmuel (Seymour J.) Metz
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<http://patriot.net/~shmuel>
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[Shmuel (Seymour J.) Metz]

In <6ab1dc82-bc83-4054-ba5a-***@m38g2000yqd.googlegroups.com>, on
11/03/2009

Post by Charly
It's the DSN returned by text during SMTP session.

Let's try this again. A DSN is, by definition, sent *after* the SMTP
session and, if sent to a forged address, is backscatter. If you really
mean DSN then you need to change your SMTP configuration to not respond
250 when the message is not deliverable.

Post by Charly
I figure out that BACKSCATTERER is going to check again my server
during next days.

AFAIK, UCEPROTECT does not test mail clients for backscatter, it simply
notes the arrival of backscatter at spam trap addresses.
--
Shmuel (Seymour J.) Metz, truly insane Spews puppet
<http://patriot.net/~shmuel>

I reserve the right to publicly post or ridicule any abusive
E-mail. Reply to domain Patriot dot net user shmuel+news to contact
me. Do not reply to ***@library.lspace.org

[Rob]

Post by Charly
Hi,
My SMTP server is blacklisted on backscatterer.org, that means I
accept unknown recipient. But it is not the case. My server return

Your assumption is incorrect. Please visit backscatterer.org to read
the real story.