Mail Server Three major components MTA MUA MDA Mail Transfer Agent sendmail, Postfix, Dovecot MUA Mail User Agent mail, Evolution MDA Mail Delivery Agent procmail, maildrop

E-mail systems are heavily dependant on name resolution. For small networks you could use /etc/hosts, but any mail system that requires Internet access needs access to a fully functional DNS server

MTA’s sendmail and Postfix Dovecot Use SMTP to send mail Dovecot is used to enable POP3 and/or IMAP to receive mail. SMTP, POP3 and IMAP are protocols, a set of rules for transferring data used by various mail transfer agents.

Reception with Dovecot Add the appropriate directive in the Dovecot configuration file. Make sure Dovecot is set to start at boot POP current version POP3 Centralized mail depository, clients download messages for processing at the local host IMAP current version IMAP4 Maintains all messages on the server

Dovecot Configuration File http://wiki.dovecot.org/QuickConfiguration /etc/dovecot.conf protocols = pop3 pop3s imap imaps listen = 10.161.25.131:10100 #ssl listen = 10.161.25.131:10943 For POP3S and IMAPS support #ssl_disable = no Activating Dovecot chkconfig dovecot on service dovecot start

sendmail Configuration http://www.sendmail.org/ Configured by two directory of files /etc/mail /usr/share/sendmail-cf Two basic configuration files sendmail-cf for incoming mail submit-cf for outgoing mail

sendmail.cf sendmail.mc access domaintable mail configuration file a macro that is easier to edit, used to generate a new sendmail.cf file access supports access control to your sendmail server, default is for local computer, host name or networks can be added to the list with a message to REJECT, DISCARD, or RELAY domaintable map different domains i.e. what.com who.com would forward mail sent to jblow@what.com to jblow@who.com

statistic submit.cf sumbit.mc virusertable Collects statistics on sendmail, can be read with the mailstats command submit.cf The main outgoing sendmail configuration file sumbit.mc a macro that is easier to edit, used to generate a new submit.cf file virusertable Supports email forwarding for users outside of your network

Basic Directives in sendmail.mc DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl FEATURE(`accept_unresolvable_domains')dnl Allow remote computers or network access to the local sendmail server you need to add their names or address to the access file. connect:10.161 RELAY

make –C /etc/mail command is used to generate new .cf files from .mc files that have been edited. Also processes files like access and virtusertable to database files (*.db) for use by sendmail