Jussi Hirvi wrote: > Is there a way to limit port access on a per-user basis? My practical goal > is to limit, who is allowed to use SMTP AUTH in Sendmail. Any possible > solutions appreciated... > > Obviously, limiting by ip will not work, since the very purpose of SMTP AUTH > is to enable mail relaying for trusted users from *anywhere*. You could use new ability of milter-greylist (from 4.0 version), that provides method to limit connections by any criteria, such as remote ip, sender/recipient address, authentication status and many more. You could extend configuration by using external helper, that can be reached by, for example, ldap or http protocols.