Neep Help with Postfix and headers_check

[SkaFan]

Debian 10 Buster with Virtualmin 6.17

Hi Forum,
I get a lot of spam from “*.ip.linodeusercontent.com” so I would like to REJECT all f these mails from users at ip.linodeusercontent.com.

It looks like this
Received:
from hubspotemail.net (172-104-227-129.ip.linodeusercontent.com [172.104.227.129]) by myhost.mydomain.tld (Postfix) with ESMTP id 61689B40C05 for user@domain.tld; Sat, 26 Mar 2022 12:31:22 +0100 (CET)

nano /etc/postfix/main.cf
I added
header_checks = pcre:/etc/postfix/header_checks

nano /etc/postfix/header_checks
If /^From:/i
/^From: .*ip.linodeusercontent.com/ REJECT
Endif

But it does not work.
and with postmap I’ll get

postmap /etc/postfix/header_checks
postmap: warning: /etc/postfix/header_checks, line 2: record is in “key: value” format; is this an alias file?
postmap: warning: /etc/postfix/header_checks, line 3: expected format: key whitespace value

[Ilia]

Hi,

What about using Webmin / Servers ⇾ SpamAssassin Mail Filter: Allowed and Denied Addresses to configure denied addresses?

[Joe]

They’re not wanting to block based on the From: address, which is what that form is for. This is about the server hostname it comes from.

[Joe]

At least, I assume they aren’t all coming from the same From: address or domain.

[Ilia]

@Joe

They’re not wanting to block based on the From: address, which is what that form is for. This is about the server hostname it comes from.

Ah, okay.

@SkaFan

and with postmap I’ll get postmap /etc/postfix/header_checks
postmap: warning: /etc/postfix/header_checks, line 2: record is in “key: value” format;

This error is coming from having a space after your From: in regex. It should rather look like this:

/^From:.*ip\.linodeusercontent\.com/ REJECT

I would also removed if endif block, as it is simply unnecessary, and be careful you cannot indent content inside of if endif block (check on that too). Moreover, I haven’t seen anyone using capital letters for If and Endif but that shouldn’t be a problem.

But it does not work.
and with postmap I’ll get

You don’t need to use postmap on files with PCRE. Simply restart Postfix.

Additionally double check that the package postfix-pcre is installed (it’s nearly impossible to have it not installed but just in case).