No fixed IP or Domain?

If you have no fixed IP and/or no Domain you can simply skip this step of the setup.
Please check the config description for sending e-mails via another mailserver or e.g. gmail.

What is Postfix?

We install Postfix as outgoing smtp mail server. If you want further information please check the Wikipedia page.


  • Install Postfix
  • Enable Postfix autostart
  • Configure Postfix
  • Set DNS SPF record (allow server to send e-mail for your domain)
  • Configure Seafile to use Postfix

Install Postifx


debconf-set-selections << EOF
postfix postfix/root_address    string
postfix postfix/rfc1035_violation       boolean false
postfix postfix/mydomain_warning        boolean
postfix postfix/mynetworks      string [::ffff:]/104 [::1]/128
postfix postfix/mailname        string  $(hostname -f)
postfix postfix/tlsmgr_upgrade_warning  boolean
postfix postfix/recipient_delim string  +
postfix postfix/main_mailer_type        select  Internet Site
postfix postfix/destinations    string  $(hostname -f), localhost.$(hostname -d)
postfix postfix/retry_upgrade_warning   boolean
# Install postfix despite an unsupported kernel?
postfix postfix/kernel_version_warning  boolean
postfix postfix/not_configured  error
postfix postfix/sqlite_warning  boolean
postfix postfix/mailbox_limit   string  0
postfix postfix/relayhost       string
postfix postfix/procmail        boolean false
postfix postfix/bad_recipient_delimiter error
postfix postfix/protocols       select  all
postfix postfix/chattr  boolean false

apt-get update && apt-get install postfix -y
dpkg-reconfigure postfix


# Config for Postfix not yet written

yum install postfix
systemctl enable postfix

Enable Postfix autostart


systemctl enable postfix

Set DNS SPF record

Your server can directly send e-mails but it's public IP needs to be added to the used domains SPF record. Otherwise e-mails will be marked as spam and nerver reach the recipient.

As a courtesy, we've come up with a generic SPF record that should work for you.
Be sure to replace with your server's IP address.

Set the DNS record type to 'TXT' and enter your SPF record.

v=spf1 a mx -all

Configure Seafile to send E-Mail via Postfix

Please check the config description for sending e-mails.