I want to offer SMTP service to my 4-5 customers. I have dedicated server (CentOS) with Postfix installed. Is there any way to create SMTP user accounts and provide SMTP service to my customers?

I will also use Policyd (Quota) to limit the number of emails can be sent per SMTP user account.

Thanks in advance.


Rephrasing what Michael has said, you need to enable smtp authentication for this to start working. If you do not enable smtp authentication then spammer's will start using your server to send out emails. You can use Postfix + Cyrus SASL + Mysql as that mentioned in the below URL to set it up.


Once this is done you can make your one web application which gives your customers to reset their password and all that value add stuff.

  • Thanks for the reply! My server is now up and running :) – Willy Jan 30 '10 at 16:47

I believe Postfix will use any SASL provider. I use these on my NetBSD machines:

courier-authlib-0.62.2 Courier Authentication Library
cy2-crammd5-2.1.23  Cyrus SASL CRAM-MD5 authentication plugin
cy2-digestmd5-2.1.23 Cyrus SASL DIGEST-MD5 authentication plugin
cy2-login-2.1.23    Cyrus SASL LOGIN authentication plugin
cy2-plain-2.1.23    Cyrus SASL PLAIN authentication plugin
cy2-sql-2.1.23      Cyrus SASL SQL authentication plugin

I then use standard flat-files for account info, as the only authenticated users are myself and my wife. If I were to use this for more, I'd consider an SQL implementation.

I then have lines like this in my main.cf file:

smtpd_sasl_auth_enable = yes 
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $myhostname
broken_sasl_auth_clients = yes

Be certain to add permit_sasl_authenticated

to places where you allow them to send mail through your machine:

smtpd_recipient_restrictions = permit_mynetworks,

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