Postfix SMTP - help wiht rbl bypass check on another smtp port

I’m using Virtualmin 3.90 and Postfix 2.6
Postfix is setup to check RBL but my clients that are using smartphones or adsl lines can’t
send emails because the ip is blacklisted on rbl.
Im trying to find a solution so that rbl check will be skiped if they will use another smtp port.
Example: for 25 port and smtp auth rbl will be active, for 587 port and smtp auth rbl will be skip.
I was searching the internet for solutions but nothing that is working.
Help please, any sugestion, thank you!



Well, a simple solution to the problem they’re seeing is to have them use their ISP as a relayhost.

So, rather than directly sending your server an email, they’d relay through their ISP – and that would resolve the RBL issue both with your server, as well as with any other servers on the Internet.

Would that setup work for them?


Thank you for your post andrey, but a solutions like that is not posible.
My “problem” with the smtp rbl bypass is important a think since many ISP block 25 port or user ip’s that
are black listed, like the ip’s from pppoe conections, 3g connections, etc.
A set o configurations to made in postfix for that situation exist?
Thank you in advance.

You could always add “smtpd_sasl_authenticated_header = yes” to your /etc/postfix/ file, and restart Postfix.

Then, when your users authenticate with your server (and they’ll need to authenticate for that to work), it’ll add a header that tells SpamAssassin that the users are legitimate.


i put “smtpd_sasl_authenticated_header = yes” and permit_sasl_authentificate in the from of check rb etc. so that it bypass rbl check if authentifated.
Is that ok? what do you think?

Yup, give it a try and see if it works :slight_smile: