Email Servers

Information And Howtos About Email Servers Such As Postfix, Dovecot, Maildrop, Sendmail

Email was the first “killer app” of the early Internet and today millions of emails are sent every day using a variety of emails servers such as postfix and sendmail. This section looks at how to use and configure email servers for sending and receiving email, mail filtering with services such as maildrop and procmail, and POP and IMAP servers such as Courier IMAP and Dovecot.

Updating Postfix’s virtual alias maps

Postfix allows you to store virtual alias maps in a text file, which tells postfix how to route virtual email addresses to real users on the system. This setting and the file location is determined in the postfix configuration file /etc/postfix/main.cf like so:

virtual_alias_maps = hash:/etc/postfix/virtual

Postfix “file too large” error message

Running postfix on a CentOS mail server I got the following error message both in a returned email and also in the log file: "cannot update mailbox … error writing message: File too large". This post looks at the erorr message in the bounce email, the log files, and the solution to the error. This error will also affect postfix mail servers on Red Hat Enterprise Linux and probably other default installs of Postfix as well.

Configure postfix to accept mail from external connections

Postfix by default on CentOS 5 and Red Hat Enterprise Linux is configured to only receive mail on the local network interface. This is good if you are not intending your server to run as a mail server but is one additional step to getting your mail server running when setting up Postfix.