sender check

By Marco Giardini at 11/26/2009 - 12:30

I have a barracuda server that receives mails, filter them and forward to a
linux system running postfix.

Both machine have a public IP (static).

The linux system is configured to be used as SMTP for sasl authenticated
users as well, besides to be used as SMTP for the people on $mynetworks
(permit_mynetworks in the smtpd_recipient_restrictions).

Unfortunatley, some spammers, have found it and use to spam local recipients
using the linux machine, avoiding so to be filtered through the barracuda
system.

I'm wondering if there is a way to allow OLNY local users or users belonging
to the domains hosted by the linux server to use SMTP.

Thanks

MG

5 comments

Re: sender check

By Wietse Venema at 11/26/2009 - 13:20

Marco Giardini:

To permit only local systems (incl. barracuda box), or users that
have a relationship with your server:

smtpd_recipient_restrictions =
permit_mynetworks permit_sasl_authenticated reject

Wietse

Re: sender check

By Marco Giardini at 11/26/2009 - 13:29

* Wietse Venema < ... at porcupine dot org> [2009-11-26 12:20:19 -0500]:

i do use:
smtpd_recipient_restrictions =
permit_mynetworks
permit_sasl_authenticated
reject_unauth_destination

but it seems from the log that spammer still send me and to other
local users spam mails.
Humm...strange....

mg

Re: sender check

By Ralf Hildebrandt at 11/26/2009 - 15:24

* Marco Giardini <m. ... at tecnogi dot com>:

Not strange. Look at the difference in the two configs.
The solution is right there.

Re: sender check

By Wietse Venema at 11/26/2009 - 13:48

Marco Giardini:

vvvvvv
permit_mynetworks permit_sasl_authenticated reject
^^^^^^
Wietse

Re: sender check

By John Peach at 11/26/2009 - 13:32

On Thu, 26 Nov 2009 18:29:00 +0100

Not at all; try reading what Wietse wrote.

reject, NOT reject_unauth_destination.