Linux – How to reject email sent to root@thedomain.tld from external sources in postfix

configurationemaillinuxpostfix

I have a postfix mail server correctly configured (I hope) and running on openSUSE 11.3. I can send email to local users from any location, but this also means that I (or anyone else) can send remote emails to the root account. How do I reject remote emails to the root account, while allowing regular users to receive email?

Best Answer

The correct way to reject certain addresses is to put this directive in the main.cf file:

smtpd_recipient_restrictions = 
    check_recipient_access hash:/etc/postfix/recipient_access
    ...

Then on the /etc/postfix/recipient_access file:

root@domain REJECT

followed by the usual:

postmap /etc/postfix/recipient_access

Related Solutions

Linux – Configure PostFix to only accept email from gmail

Ohhh, yeah! We have a sweet solution now.

We have added all of Gmails outbound servers to the firewall and only allow them to talk to port 25 on our server. Nobody else.

It works great.

FYI, Google publishes an SPF record with all their valid outbound servers according to the RFC.

So I simply added them all into the firewall for port 25 -- SMTP.

There's only one flaw in this plan.

What if Google adds or changes the SPF list?

Later on, I will make a cron job that once per day, does an SPF lookup, parses the host list, and updates the firewall restriction list.

Then it will be fool proof. Any spammers will only see a closed port, so it will get scratched off their list as a vulnerability. We won't even have the server bogged down with filtering email and such.

Postfix reject client from domains without MX records

You can achieve it with parent_domain_matches_subdomains and smtpd_sender_restrictions. Add the following to your main.cf

#/etc/postfix/main.cf
#...
parent_domain_matches_subdomains =
smtpd_sender_restrictions = check_sender_access hash:/etc/postfix/sender_blacklists
#...

#/etc/postfix/sender_blacklists
domain.com      OK
.domain.com     REJECT

Ref: postfix access Readme

Best Answer

Related Solutions

Linux – Configure PostFix to only accept email from gmail

Postfix reject client from domains without MX records

Related Topic