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Ligne 346 : |
Ligne 346 : |
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| = [[Fail2ban]] = | | = [[Fail2ban]] = |
| <filebox fn='/etc/fail2ban/jail.d/enabled.local'> | | <filebox fn='/etc/fail2ban/jail.d/enabled.local' lang='ini'> |
| [postfix] | | [postfix] |
| enabled = true | | enabled = true |
Version du 3 septembre 2023 à 17:46
Liens
Description
Postfix is a SMTP (Simple Mail Transfer Protocol) server.
Ports
port
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description
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587 incoming |
standard port for email submission by mail clients. StartTLS protocol.
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465 incoming |
SMTP with TLS encryption (deprecated)
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25 incoming |
mandatory port to receive emails from other SMTP servers
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25 outgoing |
mandatory port to send emails to other SMTP servers
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Commands
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# vérifier la configuration
sudo postfix check
# recharger la configuration
sudo postfix reload
# affiche les paramètres actuels de Postfix
postconf -pf
# affiche les paramètres par défaut
postconf -df
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/etc/postfix/main.cf
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mydomain = domain.net
# mydomain = localdomain (localdomain is replaced during installation)
myhostname = mail.domain.net
# myhostname = <hostname>.localdomain
# domain name to use in outbound mail, ex: user@myorigin
# send mail as user@$mydomain
myorigin = $mydomain
# myorigin = $myhostname
# domains to receive mail for
# add $mydomain
mydestination = $myhostname localhost.$mydomain localhost $mydomain
# mydestination = $myhostname, localhost.$mydomain, localhost
alias_maps = hash:/etc/aliases
# alias_maps = hash:/etc/aliases, nis:mail.aliases
# forward mail from the local machine only
mynetworks_style = host
# mynetworks_style = ${{$compatibility_level} < {2} ? {subnet} : {host}}
# compatibility_level = 0
# relay_domains = ${{$compatibility_level} < {2} ? {$mydestination} : {}}
# never forward mail from strangers
relay_domains =
# delivery method: direct or indirect (another smtp server)
relayhost = [smtp.internet-provider.fr]
# relayhost = (direct delivery to Internet)
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hostname
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Not sure that it is needed if localhost is used. |
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# current hostname
hostnamectl status
sudo hostnamectl set-hostname mail.domain.fr
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/etc/hosts
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127.0.0.1 localhost mail.domain.fr
::1 localhost ip6-localhost ip6-loopback mail.domain.fr
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# re-login to see the changes then run
hostname -f
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/etc/postfix/main.cf
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smtp_use_tls = yes
smtp_tls_security_level = encrypt
smtp_tls_note_starttls_offer = yes
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
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La box d’Orange bloque le port 25 en sortie ipv4 pour limiter l’envoi de spam.
L'envoie d'email doit donc se faire via le smtp d'orange. |
/etc/postfix/main.cf
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relayhost = [smtp.orange.fr]:587
smtp_sasl_password_maps = hash:/etc/postfix/sasl/orange.conf
smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
# smtp_sasl_security_options = noplaintext, noanonymous
#broken_sasl_auth_clients = yes
#smtpd_sasl_local_domain = $myhostname
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/etc/postfix/sasl/orange.conf
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[smtp.orange.fr]:587 compte@orange.fr:password
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# générer la db
sudo postmap hash:/etc/postfix/sasl/orange.conf
sudo chmod 600 /etc/postfix/sasl/orange.conf # root:root 600
sudo chmod 600 /etc/postfix/sasl/orange.conf.db # root:root 600
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/etc/postfix/main.cf
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smtpd_tls_security_level = may
#smtpd_tls_auth_only = no
smtpd_tls_key_file = /etc/letsencrypt/live/domain.net/privkey.pem
smtpd_tls_cert_file = /etc/letsencrypt/live/domain.net/fullchain.pem
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
# log level (default 0)
smtpd_tls_loglevel = 1
# 0 → no log
# 1 → Log on TLS handshake completion
# 2 → Also log levels during TLS negotiation
# 3 and 4. Use log level 3 only in case of problems. Use of log level 4 is strongly discouraged.
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Postfix supports the Dovecot SASL (Simple Authentication and Security Layer) implementation.
Dovecot is a POP/IMAP (Post Office Protocol / Interactive Message Access Protocol) server, it has its own configuration to authenticate POP/IMAP clients.
Communication between the Postfix SMTP server and Dovecot SASL happens over a UNIX-domain socket.
/etc/postfix/main.cf
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smtpd_sasl_type = dovecot
smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination
smtpd_sasl_path = private/auth
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Allow incoming port 587 (submission)
By default Postfix listen incoming STMP client connections from port 25.
In addition you may allow the port 587 to receive incoming connections from SMTP client to send emails.
StartTLS protocol is used: communications start in plain text and if possible, upgrades to TLS.
/etc/postfix/master.cf
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submission inet n - y - - smtpd
-o syslog_name=postfix/submission
-o smtpd_tls_security_level=encrypt
-o smtpd_sasl_auth_enable=yes
-o smtpd_tls_auth_only=yes
-o smtpd_reject_unlisted_recipient=no
-o smtpd_client_restrictions=$mua_client_restrictions
-o smtpd_helo_restrictions=$mua_helo_restrictions
-o smtpd_sender_restrictions=$mua_sender_restrictions
-o smtpd_recipient_restrictions=
-o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
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/etc/postfix/main.cf
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mua_client_restrictions = permit_sasl_authenticated, reject
# on BlueMail Android app, Helo command rejected, need fully-qualified hostname
# mua_helo_restrictions = reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, reject_unknown_helo_hostname
mua_helo_restrictions = reject_invalid_helo_hostname
mua_sender_restrictions = reject_non_fqdn_sender, reject_unauthenticated_sender_login_mismatch
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Allow incoming port 465 (SMTPS)
By default Postfix listen incoming STMP client connections from port 25.
In addition you may allow the port 465 to receive incoming connections from SMTP client to send emails.
Implicit TLS protocol is used: communications start encrypted with TLS.
/etc/postfix/master.cf
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smtps inet n - y - - smtpd
-o syslog_name=postfix/smtps
-o smtpd_tls_wrappermode=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_reject_unlisted_recipient=no
-o smtpd_client_restrictions=$mua_client_restrictions
-o smtpd_helo_restrictions=$mua_helo_restrictions
-o smtpd_sender_restrictions=$mua_sender_restrictions
-o smtpd_recipient_restrictions=
-o smtpd_relay_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING
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Useless if a SMTP relay is used because it will be the DKIM of the SMTP relay which will be used at the end. |
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apt install opendkim opendkim-tools
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/etc/opendkim.conf
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Domain domain.fr
KeyFile /etc/dkimkeys/dkim.key
# selectors are used to permit multiple keys under the same organization's domain name
Selector mail
# prevent trivial reformatting in header and body destroying trust
Canonicalization relaxed/simple
# if postfix is running in chroot
Socket local:/var/spool/postfix/var/run/opendkim/opendkim.sock
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/etc/default/opendkim
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# to use a Unix socket with postfix in a chroot:
RUNDIR=/var/spool/postfix/var/run/opendkim
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# generate the key
opendkim-genkey -r -s mail -b 2048 -d domain.fr
# DNS record containing the public key: mail.txt
# private key: mail.private
# copy the key
sudo mv mail.private /etc/dkimkeys/dkim.key
# check the owner of the file (root:root 600)
# configuration des droits d'accès
# add postfix in the opendkim group
sudo adduser postfix opendkim
# if postfix is running in chroot
sudo mkdir -p /var/spool/postfix/var/run/opendkim
sudo chown opendkim:opendkim /var/spool/postfix/var/run/opendkim
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mail._domainkey.domain.fr. IN TXT "v=DKIM1; h=sha256; k=rsa; s=email; p=xxx";
# mail: selector
# domain.fr: domain
# v: version
# h: hash / algorithme
# k: type de clé
# s: type de service
# p: clé publique base64
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/etc/postfix/main.cf
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# if postfix is running in chroot, there is no / before var
non_smtpd_milters = unix:var/run/opendkim/opendkim.sock
smtpd_milters = unix:var/run/opendkim/opendkim.sock
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Aliases
/etc/aliases
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postmaster: <user>
root: <user>
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# run after modification of the file /etc/aliases
sudo newaliases
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By default the local emails don't go through the SMTP relay. |
/etc/postfix/main.cf
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transport_maps = hash:/etc/postfix/transport
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- emails sent to your own domain are delivered locally
- email sent to gmail.com are delivered normally by performing MX lookup
- all other emails are delivered via the relay host
/etc/postfix/transport
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your-domain.com local
gmail.com smtp
* relay:[smtp-relay.sendinblue.com]:587
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# build the index file
sudo postmap /etc/postfix/transport
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Test
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telnet localhost 25
ehlo localhost
# vérifier que les lignes suivantes sont bien affichées
# 250-STARTTLS
# 250-AUTH
mail from: root@domain.fr
rcpt to: user@gmail.com
data
subject: test
test
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quit
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openssl s_client -connect localhost:25 -starttls smtp
openssl s_client -connect localhost:587 -starttls smtp
openssl s_client -connect localhost:465 -starttls smtp
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Log
- journalctl
- /var/log/mail.log
- /var/log/mail.err
/etc/postfix/main.cf
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# TLS logging outgoing
smtp_tls_loglevel = 1
# TLS logging incoming
smtpd_tls_loglevel = 1
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Mailboxes
By default Postifx will use mbox for the mailbox format.
/etc/postfix/main.cf
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# use maildir and store emails in the /home/<user>/maildir directory
home_mailbox = maildir/
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UFW
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# allow incoming SMTP (25) to receive emails from other SMTP servers
sudo ufw allow Postfix
# allow incoming SMTP (587) to receive emails from SMTP client over StartTLS
sudo ufw allow "Postfix Submission"
# allow incoming SMTPs (465) to receive emails from SMTP client over TLS
sudo ufw allow "Postfix SMTPS"
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/etc/fail2ban/jail.d/enabled.local
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[postfix]
enabled = true
[postfix-rbl]
enabled = true
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Installation
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apt install postfix
# General type or mail configuration: Internet site
# System mail name: domain.fr
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Erreurs
Our system has detected that 550-5.7.1 this message does not meet IPv6 sending guidelines
Our system has detected that 550-5.7.1 this message does not meet IPv6 sending guidelines regarding PTR 550-5.7.1 records and authentication.
Please review 550-5.7.1 https://support.google.com/mail/?p=IPv6AuthError for more information 550 5.7.1 .
/etc/postfix/main.cf
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inet_protocols = ipv4
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