260 lines
10 KiB
Bash
Executable File
260 lines
10 KiB
Bash
Executable File
# SMTP/IMAP: Postfix and Dovecot
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################################
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# The SMTP server is listening on port 25 for incoming mail (mail for us) and on
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# port 587 for outgoing mail (i.e. mail you send). Port 587 uses STARTTLS (not SSL)
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# and you'll authenticate with your full email address and mail password.
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#
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# The IMAP server is listening on port 993 and uses SSL. There is no IMAP server
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# listening on port 143 because it is not encrypted on that port.
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# We configure these together because postfix's configuration relies heavily on dovecot.
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# Install packages.
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source setup/functions.sh # load our functions
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source /etc/mailinabox.conf # load global vars
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apt_install \
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postfix postgrey \
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dovecot-core dovecot-imapd dovecot-lmtpd dovecot-sqlite sqlite3 \
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openssl
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mkdir -p $STORAGE_ROOT/mail
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# POSTFIX
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#########
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# Enable the 'submission' port 587 listener.
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sed -i "s/#submission/submission/" /etc/postfix/master.cf
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# Enable TLS and require it for all user authentication.
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tools/editconf.py /etc/postfix/main.cf \
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smtpd_tls_security_level=may\
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smtpd_tls_auth_only=yes \
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smtpd_tls_cert_file=$STORAGE_ROOT/ssl/ssl_certificate.pem \
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smtpd_tls_key_file=$STORAGE_ROOT/ssl/ssl_private_key.pem \
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smtpd_tls_received_header=yes
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# When connecting to remote SMTP servers, prefer TLS.
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tools/editconf.py /etc/postfix/main.cf \
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smtp_tls_security_level=may \
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smtp_tls_loglevel=2
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# Postfix will query dovecot for user authentication.
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tools/editconf.py /etc/postfix/main.cf \
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smtpd_sasl_type=dovecot \
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smtpd_sasl_path=private/auth \
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smtpd_sasl_auth_enable=yes
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# Who can send outbound mail?
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# permit_sasl_authenticated: Authenticated users (i.e. on port 587).
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# permit_mynetworks: Mail that originates locally.
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# reject_unauth_destination: No one else. (Permits mail whose destination is local and rejects other mail.)
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tools/editconf.py /etc/postfix/main.cf \
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smtpd_relay_restrictions=permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
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# Who can send mail to us?
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# reject_non_fqdn_sender: Reject not-nice-looking return paths.
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# reject_unknown_sender_domain: Reject return paths with invalid domains.
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# reject_rhsbl_sender: Reject return paths that use blacklisted domains.
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# permit_sasl_authenticated: Authenticated users (i.e. on port 587).
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# permit_mynetworks: Mail that originates locally.
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# reject_rbl_client: Reject connections from IP addresses blacklisted in zen.spamhaus.org
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# check_policy_service: Apply greylisting using postgrey.
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#
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# Notes:
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# permit_dnswl_client can pass through mail from whitelisted IP addresses, which would be good to put before greylisting
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# so these IPs get mail delivered quickly. But when an IP is not listed in the permit_dnswl_client list (i.e. it is not
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# whitelisted) then postfix does a DEFER_IF_REJECT, which results in all "unknown user" sorts of messages turning into
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# "450 4.7.1 Client host rejected: Service unavailable". This is a retry code, so the mail doesn't properly bounce.
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tools/editconf.py /etc/postfix/main.cf \
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smtpd_sender_restrictions="reject_non_fqdn_sender,reject_unknown_sender_domain,reject_rhsbl_sender dbl.spamhaus.org"
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tools/editconf.py /etc/postfix/main.cf \
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smtpd_recipient_restrictions=permit_sasl_authenticated,permit_mynetworks,"reject_rbl_client zen.spamhaus.org","check_policy_service inet:127.0.0.1:10023"
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# Have postfix listen on all network interfaces, set our name (the Debian default seems to be localhost),
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# and set the name of the local machine to localhost for xxx@localhost mail (but I don't think this will have any effect because
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# there is no true local mail delivery). Also set the banner (must have the hostname first, then anything).
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tools/editconf.py /etc/postfix/main.cf \
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inet_interfaces=all \
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myhostname=$PUBLIC_HOSTNAME\
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smtpd_banner="\$myhostname ESMTP Hi, I'm a Mail-in-a-Box (Ubuntu/Postfix; see https://github.com/joshdata/mailinabox)" \
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mydestination=localhost
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# Handle all local mail delivery by passing it directly to dovecot over LMTP.
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tools/editconf.py /etc/postfix/main.cf virtual_transport=lmtp:unix:private/dovecot-lmtp
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# Use a Sqlite3 database to check whether a destination email address exists,
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# and to perform any email alias rewrites.
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tools/editconf.py /etc/postfix/main.cf \
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virtual_mailbox_domains=sqlite:/etc/postfix/virtual-mailbox-domains.cf \
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virtual_mailbox_maps=sqlite:/etc/postfix/virtual-mailbox-maps.cf \
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virtual_alias_maps=sqlite:/etc/postfix/virtual-alias-maps.cf \
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local_recipient_maps=\$virtual_mailbox_maps
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# Here's the path to the database.
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db_path=$STORAGE_ROOT/mail/users.sqlite
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# SQL statement to check if we handle mail for a domain, either for users or aliases.
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cat > /etc/postfix/virtual-mailbox-domains.cf << EOF;
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dbpath=$db_path
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query = SELECT 1 FROM users WHERE email LIKE '%%@%s' UNION SELECT 1 FROM aliases WHERE source LIKE '%%@%s'
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EOF
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# SQL statement to check if we handle mail for a user.
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cat > /etc/postfix/virtual-mailbox-maps.cf << EOF;
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dbpath=$db_path
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query = SELECT 1 FROM users WHERE email='%s'
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EOF
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# SQL statement to rewrite an email address if an alias is present.
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cat > /etc/postfix/virtual-alias-maps.cf << EOF;
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dbpath=$db_path
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query = SELECT destination FROM aliases WHERE source='%s'
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EOF
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# Create an empty database if it doesn't yet exist.
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if [ ! -f $db_path ]; then
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echo Creating new user database: $db_path;
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echo "CREATE TABLE users (id INTEGER PRIMARY KEY AUTOINCREMENT, email TEXT NOT NULL UNIQUE, password TEXT NOT NULL, extra);" | sqlite3 $db_path;
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echo "CREATE TABLE aliases (id INTEGER PRIMARY KEY AUTOINCREMENT, source TEXT NOT NULL UNIQUE, destination TEXT NOT NULL);" | sqlite3 $db_path;
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fi
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# DOVECOT
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#########
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# The dovecot-imapd dovecot-lmtpd packages automatically enable IMAP and LMTP protocols.
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# Set the location where we'll store user mailboxes.
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tools/editconf.py /etc/dovecot/conf.d/10-mail.conf \
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mail_location=maildir:$STORAGE_ROOT/mail/mailboxes/%d/%n \
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mail_privileged_group=mail \
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first_valid_uid=0
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# Require that passwords are sent over SSL only, and allow the usual IMAP authentication mechanisms.
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# The LOGIN mechanism is supposedly for Microsoft products like Outlook to do SMTP login (I guess
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# since we're using Dovecot to handle SMTP authentication?).
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tools/editconf.py /etc/dovecot/conf.d/10-auth.conf \
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disable_plaintext_auth=yes \
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"auth_mechanisms=plain login"
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# Query our Sqlite3 database, and not system users, for authentication.
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sed -i "s/\(\!include auth-system.conf.ext\)/#\1/" /etc/dovecot/conf.d/10-auth.conf
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sed -i "s/#\(\!include auth-sql.conf.ext\)/\1/" /etc/dovecot/conf.d/10-auth.conf
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# Configure how to access our Sqlite3 database. Not sure what userdb is for.
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cat > /etc/dovecot/conf.d/auth-sql.conf.ext << EOF;
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passdb {
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driver = sql
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args = /etc/dovecot/dovecot-sql.conf.ext
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}
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userdb {
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driver = static
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args = uid=mail gid=mail home=$STORAGE_ROOT/mail/mailboxes/%d/%n
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}
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EOF
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# Configure the SQL to query for a user's password.
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cat > /etc/dovecot/dovecot-sql.conf.ext << EOF;
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driver = sqlite
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connect = $db_path
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default_pass_scheme = SHA512-CRYPT
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password_query = SELECT email as user, password FROM users WHERE email='%u';
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EOF
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chmod 0600 /etc/dovecot/dovecot-sql.conf.ext # per Dovecot instructions
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# Disable in-the-clear IMAP and POP because we're paranoid (we haven't even
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# enabled POP).
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sed -i "s/#port = 143/port = 0/" /etc/dovecot/conf.d/10-master.conf
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sed -i "s/#port = 110/port = 0/" /etc/dovecot/conf.d/10-master.conf
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# Have dovecot provide authorization and LMTP (local mail delivery) services.
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#
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# We have dovecot listen on a Unix domain socket for these services
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# in a manner that made postfix configuration above easy.
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#
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# We also have dovecot listen on port 10026 (localhost only) for LMTP
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# in case we have other services that want to deliver local mail, namely
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# spampd.
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#
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# Also increase the number of allowed connections per mailbox because we
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# all have so many devices lately.
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cat > /etc/dovecot/conf.d/99-local.conf << EOF;
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service auth {
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unix_listener /var/spool/postfix/private/auth {
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mode = 0666
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user = postfix
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group = postfix
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}
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}
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service lmtp {
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unix_listener /var/spool/postfix/private/dovecot-lmtp {
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user = postfix
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group = postfix
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}
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inet_listener lmtp {
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address = 127.0.0.1
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port = 10026
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}
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}
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protocol imap {
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mail_max_userip_connections = 20
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}
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EOF
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# postmaster_address seems to be required or LMTP won't start
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tools/editconf.py /etc/dovecot/conf.d/15-lda.conf \
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postmaster_address=postmaster@$PUBLIC_HOSTNAME
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# Drew Crawford sets the auth-worker process to run as the mail user, but we don't care if it runs as root.
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# Enable SSL and specify the location of the SSL certificate and private key files.
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tools/editconf.py /etc/dovecot/conf.d/10-ssl.conf \
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ssl=required \
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"ssl_cert=<$STORAGE_ROOT/ssl/ssl_certificate.pem" \
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"ssl_key=<$STORAGE_ROOT/ssl/ssl_private_key.pem" \
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# SSL CERTIFICATE
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mkdir -p $STORAGE_ROOT/ssl
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if [ ! -f $STORAGE_ROOT/ssl/ssl_certificate.pem ]; then
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# Generate a new private key if one doesn't already exist.
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openssl genrsa -out $STORAGE_ROOT/ssl/ssl_private_key.pem 2048
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fi
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if [ ! -f $STORAGE_ROOT/ssl/ssl_cert_sign_req.csr ]; then
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# Generate a certificate signing request if one doesn't already exist.
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openssl req -new -key $STORAGE_ROOT/ssl/ssl_private_key.pem -out $STORAGE_ROOT/ssl/ssl_cert_sign_req.csr \
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-subj "/C=$CSR_COUNTRY/ST=/L=/O=/CN=$PUBLIC_HOSTNAME"
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fi
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if [ ! -f $STORAGE_ROOT/ssl/ssl_certificate.pem ]; then
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# Generate a SSL certificate by self-signing if a SSL certificate doesn't yet exist.
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openssl x509 -req -days 365 \
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-in $STORAGE_ROOT/ssl/ssl_cert_sign_req.csr -signkey $STORAGE_ROOT/ssl/ssl_private_key.pem -out $STORAGE_ROOT/ssl/ssl_certificate.pem
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fi
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echo
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echo "Your SSL certificate's fingerpint is:"
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openssl x509 -in /home/user-data/ssl/ssl_certificate.pem -noout -fingerprint
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echo
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# PERMISSIONS / RESTART SERVICES
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# Ensure configuration files are owned by dovecot and not world readable.
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chown -R mail:dovecot /etc/dovecot
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chmod -R o-rwx /etc/dovecot
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# Ensure mailbox files have a directory that exists and are owned by the mail user.
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mkdir -p $STORAGE_ROOT/mail/mailboxes
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chown -R mail.mail $STORAGE_ROOT/mail/mailboxes
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# Restart services.
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service postfix restart
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service dovecot restart
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# Allow mail-related ports in the firewall.
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ufw_allow smtp
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ufw_allow submission
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ufw_allow imaps
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