On 08/20/2014 07:44 AM, Daniele Nicolodi wrote:
On 20/08/2014 10:56, ml ml wrote:
By default my postfix accepted those mails until it found out that the
recipent does not exists. Then postfix tries to send back that "550
User Unknown" error mail.
I doubt that Postfix by default accepts mail for users it does not know
about, but anyway...
However, the sender is fake. Therefore the mails get stuck on my postfix mta.
I now enabled recipient address verification. In that case my postfix
mta will reject the mails already in the rcpt to stream. Which is
great.
However, i now got blacklisted by backscatterer:
I'm not surprised.
The source of this problem seem to be the emtpy address verify
probes/mails. In this case this no spam or mass mails or anything.
Just a lot of mails and empty from sender addresses and a lot of mail
traffic.
The reason why you are blacklisted is the backscatter caused by your
late rejection of incoming messages, NOT the recipient verify probes.
And if you need to use recipient verify for domains that are not under
your control, you are definitely doing something wrong: why do you
accept mail from external sources directed to domains you do not
control? This smells like an open relay to me.
Cheers,
Daniele
You're right that he probably has open relays and other security/leak
problems. He has most likely studied his logs and other items and tried
to fix these things on his own and how has the problems that you and
Larry are describing. He's stuck and trying to get the best resolution
to fix the gaps. Without support from people in the know, he'd probably
dig himself in a deeper hole.
-- L. James
--
L. D. James
lja...@apollo3.com
www.apollo3.com/~ljames
