Configure exim4 mail server

In this article exim will deliver the emails to Maildir ~/Maildir/new first create the Maildir in user home directory:

sudo mkdir -p /home/mailuser/Maildir/{new,cur,tmp}
sudo chown -R mailuser:mailuser /home/mailuser/Maildir

Install the mail server exim4 and the imap and pop3 server dovecot:

pacman -Sy exim dovecot

This is a tested /etc/mail/exim.conf make changes for your hosts names and domains and put it to its working folder:

primary_hostname = mail.example.com
domainlist local_domains = @ : localhost : example.com
domainlist relay_to_domains =
hostlist   relay_from_hosts = localhost
acl_smtp_rcpt =         acl_check_rcpt
.ifdef _HAVE_PRDR
acl_smtp_data_prdr =    acl_check_prdr
.endif
acl_smtp_data =         acl_check_data
daemon_smtp_ports = 25 : 465 : 587
qualify_domain = example.com
allow_domain_literals
never_users = root
host_lookup = *
dns_dnssec_ok = 1
.ifdef _HAVE_PRDR
prdr_enable = true
.endif
log_selector = +smtp_protocol_error +smtp_syntax_error \
        +tls_certificate_verified
ignore_bounce_errors_after = 30d
timeout_frozen_after = 30d
begin acl
acl_check_rcpt:
  accept  hosts = :
          control = dkim_disable_verify
  deny    message       = Restricted characters in address
          domains       = +local_domains
          local_parts   = ^[.] : ^.*[@%!/|]
  deny    message       = Restricted characters in address
          domains       = !+local_domains
          local_parts   = ^[./|] : ^.*[@%!] : ^.*/\\.\\./
  accept  local_parts   = postmaster
          domains       = +local_domains
  accept  hosts         = +relay_from_hosts
          control       = submission
          control       = dkim_disable_verify
  accept  authenticated = *
          control       = submission
          control       = dkim_disable_verify
  require message       = nice hosts say HELO first
          condition     = ${if def:sender_helo_name}
  require message = relay not permitted
          domains = +local_domains : +relay_to_domains
  accept
.ifdef _HAVE_PRDR
acl_check_prdr:
  warn  set acl_m_did_prdr = y
.endif
  accept
acl_check_data:
  deny    message    = maximum allowed line length is 998 octets, \
                       got $max_received_linelength
          condition  = ${if > {$max_received_linelength}{998}}
  deny    !verify =     header_syntax
          message =     header syntax
          log_message = header syntax ($acl_verify_message)
  accept
begin routers
.ifdef ROUTER_SMARTHOST
smarthost:
  driver = manualroute
  domains = ! +local_domains
  transport = smarthost_smtp
  route_data = ROUTER_SMARTHOST
  ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1
  no_more
.else
dnslookup:
  driver = dnslookup
  domains = ! +local_domains
  transport = remote_smtp
  ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
  dnssec_request_domains = *
  no_more
.endif
system_aliases:
  driver = redirect
  allow_fail
  allow_defer
  data = ${lookup{$local_part}lsearch{/etc/mail/aliases}}
  file_transport = address_file
  pipe_transport = address_pipe
userforward:
  driver = redirect
  check_local_user
  file = $home/.forward
  no_verify
  no_expn
  check_ancestor
  file_transport = address_file
  pipe_transport = address_pipe
  reply_transport = address_reply
localuser:
  driver = accept
  check_local_user
  transport = local_delivery
  cannot_route_message = Unknown user
begin transports
remote_smtp:
  driver = smtp
  message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
.ifdef _HAVE_DANE
  dnssec_request_domains = *
  hosts_try_dane = *
.endif
.ifdef _HAVE_PRDR
  hosts_try_prdr = *
.endif
smarthost_smtp:
  driver = smtp
  message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
  multi_domain
.ifdef _HAVE_TLS
  hosts_require_tls = *
  tls_verify_hosts = *
  tls_try_verify_hosts = *
  tls_sni = ROUTER_SMARTHOST
.ifdef _HAVE_OPENSSL
  tls_require_ciphers = HIGH:!aNULL:@STRENGTH
.endif
.ifdef _HAVE_GNUTLS
  tls_require_ciphers = SECURE192:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1
.endif
.endif
.ifdef _HAVE_PRDR
  hosts_try_prdr = *
.endif
local_delivery:
  driver = appendfile
  directory = /home/$local_part_data/Maildir/new
  delivery_date_add
  envelope_to_add
  return_path_add
  group = mail
address_pipe:
  driver = pipe
  return_output
address_file:
  driver = appendfile
  delivery_date_add
  envelope_to_add
  return_path_add
address_reply:
  driver = autoreply
begin retry
*                      *           F,2h,15m; G,16h,1h,1.5; F,4d,6h
begin rewrite
begin authenticators
dovecot_login:
  driver = dovecot
  public_name = LOGIN
  server_socket = /var/run/dovecot/auth-client
  server_set_id = $auth1
dovecot_plain:
  driver = dovecot
  public_name = PLAIN
  server_socket = /var/run/dovecot/auth-client
  server_set_id = $auth1

then restart or start the exim server:

systemctl restart exim

substitute SMTP ports

These are smpt ports one can try for isp if they let them to send mail:

25, 2525, 8025, 587 and 465 for ssl

test the exim erver with this command:

exim -d -bt user_name@your_domain.com

Configure the exim4 mail server.

substitute SMTP ports