Receipt Verification

[audiotron2002]

How can i stop scalix from accepting these? This is how microsoft works. Is there a similar option in scalix?

http://technet.microsoft.com/en-us/library/aa998898%28EXCHG.80%29.aspx



smtp# telnet mail.XXX.net 25
Trying XXX.XXX.XXX.XXX...
Connected to mail.XXX.net.
Escape character is '^]'.
220 mail.XXX.net ESMTP Scalix SMTP Relay 11.4.5.13150; Tue, 10 Aug 2010 09:51:10 -0400 (EDT)
helo bla.com
250 mail.XXX.net Hello SMTP.XXX.net [XXX.XXX.XXX.XXX], pleased to meet you
mail from:<>
250 ... Sender ok
rcpt to:<sdsdsdsd@ANYDOMAIN.com>
250 Ok

[BaldBoy]

Unfortunately you can't by Scalix only. Empty reverse path (mail from:<>) is legitimate when remote mail transfer agents deliver notification messages eg. "undeliverable mail".

There are several tools out there which can help you in the fight against backscattering (ASSP, SpamAssassin etc.)

[Valerion]

You do need to allow this for certain things (like NDN's) to work properly. If you don't accept them, your users will never be notified that mail was not delivered, and by experience I can tell you they will assume it was and complain later on.

If you really want to stop these, you can do it as a sendmail milter, then send all messages from the SMTP relay to sendmail before delivery into Scalix. The milter framework should allow for this easily enough. You can also add individual domains and addresses in the SMTP Relay file's configuration to block, but I think the empty address is invalid there.

[audiotron2002]

then why does exchange have this support built in and not sclaix?

[Valerion]

The Exchange article you linked to is about recipient filtering, i.e. if I receive a mail for user@domain.com (where this is my own domain), it will not be delivered. You can do that in Scalix by adding the relevant entries to the smtpd.cfg file in /var/opt/scalix/??/s/sys. There are some comments there to show you the correct syntax.

If you do indeed block the empty address you will be violating the SMTP RFC, which Scalix does not support.

[BaldBoy]

Code: Select all

then why does exchange have this support built in and not sclaix?

Because Scalix IS NOT Exchange.

Probably we're talking about two different problems.

If you want to block empty "mail from" messages ... then ... you're warmly suggested not to (as also pointed out by valerion).

If you want to block messages which has a "receipt to" addressed to non existing email address of your server it's a different matter.

By default Scalix's SMTP relay accepts every address which is bound to your local domains even if they're not in your directory (i.e. no user or group has that email address): this is due to the fact that Scalix's unknown email addresses may be handled later by sendmail.

If this is the problem I'd suggest to read this thread: you'll find your solution.
http://www.scalix.com/forums/viewtopic.php?f=23&t=12513