Common Problems

From Oxxus Wiki

Most services implemented within Linux OS server can be used right out-of- the-box, the same applies to email services. There are, however, several issues that have to be taken care off.

ISP permissions for accessing 25 TCP port

One of the most important ones nowadays is ISP permissions for accessing 25 TCP port. It's prohibited at most ISP as anti-spam measure, so if server cannot be reached at default 25 for SMTP, email services can be accessed via other, user defined port which will forward all incoming requests to default port 25. This can be achieved by redirection directive of iptables services available by default with every Linux OS distro.

Authenticating to SMTP Service

Another issue would be authenticating to SMTP service, as it's now required with every SMTP server, also as anti-spam measure.

With SMTP authentication no-one will be able to send emails unless it's authenticated to SMTP server. There are several SMTP authentication ways like PLAIN , SSL or TLS. While all of them will work, it's recommended to use encrypted login via SSL or TLS. Which one of those is offered is up to SMTP server maintainer to include.

To work correctly, SMTP and POP3/IMAP services have to be bind to global, Internet accessible IP address, as none of localhost will do.