GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
* Sign Up! *

Support
Customer Portal
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

The Mail Server: Sendmail and Dovecot

bullet Introduction

Running your own mail server lets your domain send and receive email under its own name. A complete setup has three parts: a mail transfer agent (MTA) that sends and receives mail over SMTP, a mailbox store that holds delivered mail and serves it to clients over IMAP/POP3, and the clients people read mail with. This documentation uses Sendmail as the MTA and Dovecot as the mailbox store on both FreeBSD 15 and Rocky Linux 10. Spam filtering (SpamAssassin), virus scanning (ClamAV), and webmail (Roundcube) each have their own pages.

 

bullet Installing Sendmail and Dovecot

On FreeBSD 15, the default system mailer is dma, a small send-only agent, and the copy of Sendmail remaining in the base system is deprecated and built without the SASL support that SMTP authentication (below) requires. Install the full Sendmail package alongside Dovecot, point the system mailer at it, and start both:

# pkg install sendmail dovecot
# cp /usr/local/etc/mail/mailer.conf.sendmail /usr/local/etc/mail/mailer.conf
# sysrc sendmail_enable=YES
# sysrc sendmail_submit_enable=YES
# service sendmail start
# sysrc dovecot_enable=YES
# service dovecot start

On Rocky Linux 10, no MTA is installed by default; install Sendmail (packaged in EPEL) and Dovecot, then make Sendmail the system mailer:

# dnf install epel-release
# dnf install sendmail sendmail-cf dovecot dovecot-pigeonhole
# alternatives --set mta /usr/sbin/sendmail.sendmail
# systemctl enable --now sendmail
# systemctl enable --now dovecot

 

bullet Configuring Sendmail

Sendmail is configured by editing a .mc macro file in /etc/mail and rebuilding — the same directory on both systems. On FreeBSD, first tell the rebuild to use the Sendmail package's configuration templates by adding one line to /etc/make.conf:

SENDMAIL_CF_DIR=/usr/local/share/sendmail/cf

After any change, rebuild and restart:

# FreeBSD:    cd /etc/mail && make install restart
# Rocky Linux: make -C /etc/mail && systemctl restart sendmail

The pieces you will set up most often:

  • local-host-names — the domains this server accepts mail for.

  • Aliases (/etc/aliases, rebuilt with newaliases) — forward one local address to another mailbox, to several recipients, or to an external address.

  • virtusertable — route addresses for hosted domains to specific mailboxes ("virtual users"), so sales@example.com and sales@another.example can land in different places.

  • access — allow or reject mail from particular senders, domains, or networks for basic spam control.

 

bullet Dovecot and SMTP Authentication

Dovecot serves delivered mail to clients over IMAP and POP3 (use the SSL/TLS variants, IMAPS and POP3S). It also provides the authentication that lets your users send mail through the server from anywhere — "SMTP AUTH" — by exposing an auth socket that Sendmail consults. Dovecot's Sieve plugin (the pigeonhole package on Rocky Linux) powers the server-side filters and vacation messages that Roundcube sets up.

Two useful commands while configuring: doveconf -n prints the active configuration (omitting defaults), and doveadm who lists who is currently connected.

 

bullet Configuring Mail Clients

Once the server is running, configure a desktop or phone mail client with: incoming IMAP (or POP3) on your server's hostname using SSL/TLS; outgoing SMTP on the submission port (587) with SSL/TLS and authentication turned on; and the user's full email address and password as credentials. Open the matching ports in your firewall (SMTP, submission, IMAPS, POP3S).

 

bullet Documentation


Toll Free 1-866-GSP-4400 • 1-301-464-9363 • service@gsp.com
Copyright © 1994-2026 GSP Services, Inc.