On 14/05/2019 01:27, Wietse Venema wrote:
> Wietse Venema:
>> If you look at the non-VPN captures, then you will see the following:
>>
>> - In one trace, we see a client ACK 138, followed by a client packet
>> with "." (data 443:446, ACK 138, and a timestamp field
>> tht is unlike those of al
Wietse Venema:
> If you look at the non-VPN captures, then you will see the following:
>
> - In one trace, we see a client ACK 138, followed by a client packet
> with "." (data 443:446, ACK 138, and a timestamp field
> tht is unlike those of al other packets in the stream).
>
> - In the
Wietse Venema:
> fhare:
> > Hello list,
> >
> > Bit of a weird one here. I have hosts at AWS sending mail across a
> > Checkpoint VPN to my main private relay server (it basically serves to relay
> > mail to O365 for in house applications). The problem is that the sending
> > client never
fhare:
> Hello list,
>
> Bit of a weird one here. I have hosts at AWS sending mail across a
> Checkpoint VPN to my main private relay server (it basically serves to relay
> mail to O365 for in house applications). The problem is that the sending
> client never receives BYE from server after
Wietse, you're the best!
Thank you very very much :)
- Original Message -
From: "Wietse Venema"
To: "postfix-users"
Sent: Monday, May 13, 2019 4:46:57 PM
Subject: Re: Postfix as an outgoing spam filter. How to block email for unknown
senders in local network?
Wietse Venema:
>
Wietse Venema:
> sandermo...@telenet.be:
> > Can't we use the 'smtpd_sender_restrictions = check_sender_access
> > ...' option on port 26 only using parameters in master.cf ?
>
> Yes.
>
> /etc/postfix/master.cf
>:26 .. .. .. .. .. .. .. smtpd
> -o {
Hello list,
Bit of a weird one here. I have hosts at AWS sending mail across a
Checkpoint VPN to my main private relay server (it basically serves to relay
mail to O365 for in house applications). The problem is that the sending
client never receives BYE from server after QUIT. The mail goes
sandermo...@telenet.be:
> Can't we use the 'smtpd_sender_restrictions = check_sender_access
> ...' option on port 26 only using parameters in master.cf ?
Yes.
/etc/postfix/master.cf
:26 .. .. .. .. .. .. .. smtpd
-o { smtpd_sender_restrictions=$outbound_sender_restrictions }
On 2019-05-13 12:03 BST, sandermo...@telenet.be wrote:
> The hackers forged the from address so our notifications were sent
> to that address instead, and we want to prevent that from happening
> again.
I'm offering the following in the hope that someone will tell me if
it's all wrong...
a) Add
Hi Wietse,
Thanks for clearing that out. I read the first part of the manual and thought
it would block if postfix is not the final destination but I didn't really
understand the AND part of the sentence but now I do. So it's not the option I
need. My bad! ;)
Now, to get back to your
Wietse Venema:
> sandermo...@telenet.be:
> > After some googling I found that the "reject_unknown_sender_domain"
> > option should reject mail if Postfix isn't the sender's domain
> > final destination so that sounds good too. I enabled that option
> > but it doesn't seem to work?
>
> It works as
sandermo...@telenet.be:
> After some googling I found that the "reject_unknown_sender_domain"
> option should reject mail if Postfix isn't the sender's domain
> final destination so that sounds good too. I enabled that option
> but it doesn't seem to work?
It works as promised.
We have a postfix system that accepts mail from our internal network. It scans
emails for virusses and spam before delivering it.
It's listening on port 26 and so far everything works.
Last night one of our users's mailbox got hacked and they tried to send a lot
of spam emails. Most of it got
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