Hi All,

i have setup Postfix with MailScanner/SA etc.

To allow relay from mail servers i was adding the remote static IPs
to "mynetworks" on postfix main.cf and for the mail shield (mx records from outside)
i added the remote domains to /etc/postfix/transport with the related fqdn of the
final destination. (of course i have security checks, custom ports and other stuff not for your concerns)

everything is working great and smooth,
i just try to understand if it's possible in postfix to bind the
sender domain to the IP is relaying from,

let me explain,
remote mail server ip: 1.1.1.1
sent from domain: @contoso.com

if the remote mail server send an email it goes to the relay server,
postfix check if the sending IP allow relay, and permit this IP to relay,
so far so good, but i want to tell postfix regardless of the allowing relay
to allow not just the remote IP but also the "MAIL FROM:" domain from the envelpoe.

the idea is, if it comes from server ip: 1.1.1.1 and from @contoso.com it will be Allow,
if it comes from server ip: 1.1.1.1 but from @fabrikam.com it will be deny,
i want to deny it at the smtp protocol level, im trying to prevent spambot or
open relay proxy if the remote site will get virus or any trojan.

Thank you in advance.

You can try to create a "header_check" rule file.
In that file you can specify:

/^From: .*@fabrikam\.com/ DISCARD

This way any email coming from that domain would be discarded.

1 members found this post helpful.

Thanks for the answer,
but i dont see how it match my needs..
first, fabrikam.com is an example, it can be any domain other then the true originating domain (contoso.com for example).
and how exactly i bind the domain to the mail server ip?
and how it deny at the smtp protocol level?

sorry, but you read the question before answring?

Example, or actual domain, I think you should try it before discarding what you don't "see".
It matches as
I found this answer very interesting and made a comment on my blog to have later, if/when I need it.

Don't knock it until you've tried it, or at least researched the given response.

References:
http://www.postfix.org/header_checks.5.html
http://www.ganino.com/how_to_filter_..._header_checks
http://superuser.com/questions/89628...-with-antispam

you joking? try it?
im header_checks writer\exploiter pro,
this is even not a reasonable answer to what i'm after.

Anyway, can some postfix master redeem me?

And yet you're here asking us.