...2. Edit your /etc/postfix/header_checks.pcre
The format can be as simple as :
<REGEX> <ACTION>
Include something like
/^From:.*badaddress@spammerdomain\.com\.br/ REJECT
3. Postfix usually comes with a header_checks file with lots of good instructions
Mine has been renamed...
...Since we don't want to receive any emails from correspondents in Russia or Ukraine,
the following lines in header_checks.pcre are stopping a quantity of spam being processed by our email server.
/^From:.*\.ru>?$/i REJECT
/^From:.*\.ua>?$/i REJECT
More goodness being done by postfix. [wink]
...after using a nice file of header_checks for a coupla weeks, We're getting this job done.
Many lines in header_checks.pcre like this one :
/^From:.*@linkedin\.com/i REJECT SPAM is rejected. Sender address is blacklisted.
For the most persistent spammers, our perimeter firewall now...
For the moment we're staying within postfix, since I have little experience with SA.
Also, I like giving the unwanted sender/s a specially crafted REJECT message which is intended to cause them confusion. It appears to work.
There's some good and relevant info at the bottom of this page...
We use a different technique to reject emails spoofing our domain/s. Greylisting.
It is very successful.
On CentOS the package is postgrey.
Simply, many spammers make up random usernames, and typically only make a single attempt to deliver their payloads.
So those emails are never accepted by...
Yes, I've been contemplating something similar.
Create an email folder/file called "Blocked".
Move emails to the Blocked folder/file as desired.
Nightly script to parse the users' Blocked emails and update the postfix header_checks file as needed to include REJECT.
Since we only use webmail, and...
This is another good thread for postifx on CentOS.
https://wiki.centos.org/HowTos/postfix
See especially the part/s about ensuring you're not an open relay.
HTH
...is positive.
header_checks = pcre:/etc/postfix/header_checks.pcre
And header_checks.pcre contains many lines similar to following :
/^From:.*\@unwanted_domain\.com\/i REJECT Your SPAM from Mailchimp is rejected. Your domain is reported as blacklisted.
Suggesting that a domain has...
Sadly, it seems the smptd_recipient_restrictions are not sufficient to block selected junk spewing out from Mailchimp's servers.
I'm not surprised, since Mailchimp has significant resources to ensure their messages are not easily blocked.
From the mail logs, it looks like Mailchimp is forging...
Chris
I've blown a few years of dust off some good old texts.
Postfix (2001) by Richard Blum ; and
The Book of Postfix (2005) by Ralf Hildenbrandt and Patrick Koetter
Yes, I have some dead-tree versions in my library.
Also...
Chris
Thanks for the great explanation. I couldn't find that anywhere else. I give you a star.
I agree its easy, almost obvious, when you know how/why.
I'm not a complete idiot. There's still a few pieces missing.
[SOLVED]
Looks like my PBKAC
smtpd_sender_restrictions = check_sender_access hash:/etc/postfix/sender_access
I had incorrectly included the above instruction within section smptd_sender_restrictions =
Now moved to section smptd_recipient_restrictions = and appears working as intended.
This...
Hi forum
We like and have been using Postfix in our small business for many years.
We have a small~ish list of sender domains that we reject using the usual details in /etc/postfix/sender_access and the following line in /etc/postfix/main.cf
smtpd_sender_restrictions = check_sender_access...
Thanks feherke for suggestions. Unfortunately, all those options throw errors, but your input is greatly appreciated.
Thanks rharsh for suggestion. Yo the man. It works.
BTW, I'm connecting to an an old SQL Server 2005 Express database.
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