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| − | Postfix är en mail transfer agent(MTA) som kan skicka och ta emot email. Postfix används ofta tillsammans med [[Dovecot]]. Postfix kom redan 1986 men skrevs om 1997, ca 32% av dagens publika mailservrar kör Postfix.
| + | #REDIRECT [[Mailserver]] |
| − | | + | [[Category:Guider]] |
| − | ==Förberedelse==
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| − | Öppna port i brandväggen.
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| − | *25 (SMTP)
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| − | | |
| − | Och skapa ett A och MX record i DNSen som spekar mot mailservern.
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| − | | |
| − | ==Installation==
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| − | apt-get install postfix postfix-pcre
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| − | | |
| − | Om man vill kunna skicka testmails(swaks) och enkelt styra mailboxen(mutt).
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| − | apt-get install mutt swaks
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| − | | |
| − | ==Konfiguration==
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| − | Konfigurations filerna finns under <code>/etc/postfix</code>
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| − | | |
| − | ===LDAP===
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| − | Man kan enkelt koppla Postfix mot en LDAP server för autentisering, vilken mail och mailalias en användare ska ha och hur mycket lagring användare får.
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| − | | |
| − | '''Förberedelse'''
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| − | | |
| − | En uppsatt [[OpenLDAP]] server med ett postfix schema inlagt. Och en [[Dovecot]] server som också ska LDAP anslutas.
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| − | | |
| − | '''Installation'''
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| − | apt-get install postfix-ldap
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| − | | |
| − | <div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
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| − | <code>main.cf</code> Detta är main konfigurations filen.
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| − | <div class="mw-collapsible-content">
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| − | <syntaxhighlight lang=bash>#!/bin/bash
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| − | ###################################################################################################
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| − | ### Base Settings ###
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| − | #####################
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| − | | |
| − | # Listen on all interfaces
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| − | inet_interfaces = all
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| − | | |
| − | # Use TCP IPv4
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| − | inet_protocols = ipv4
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| − | | |
| − | # Greet connecting clients with this banner
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| − | smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
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| − | | |
| − | # Fully-qualified hostname
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| − | myhostname = mail.example.com
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| − | | |
| − | # Do not append domain part to incomplete addresses (this is the MUA's job)
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| − | append_dot_mydomain = no
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| − | | |
| − | # Trusted networks/hosts (these are allowed to relay without authentication)
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| − | mynetworks =
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| − | # Local
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| − | 127.0.0.0/8
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| − | # External
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| − | 1.2.3.4/32
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| − | | |
| − | | |
| − | ###################################################################################################
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| − | ### Local Transport ###
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| − | #######################
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| − | | |
| − | # Disable local transport (so that system accounts can't receive mail)
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| − | local_transport = error:Local Transport Disabled
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| − | | |
| − | # Don't use local alias maps
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| − | alias_maps =
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| − | | |
| − | # Local domain (could be omitted, since it is automatically derived from $myhostname)
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| − | mydomain = example.com
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| − | | |
| − | # Mails for these domains will be transported locally
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| − | mydestination =
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| − | $myhostname
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| − | localhost.$mydomain
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| − | localhost
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| − | | |
| − | | |
| − | ###################################################################################################
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| − | ### Virtual Transport ###
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| − | #########################
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| − | | |
| − | # Deliver mail for virtual recipients to Dovecot
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| − | virtual_transport = dovecot
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| − | | |
| − | # Process one mail at one time
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| − | dovecot_destination_recipient_limit = 1
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| − | | |
| − | # Valid virtual domains
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| − | virtual_mailbox_domains = hash:/etc/postfix/virtual_domains
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| − | | |
| − | # Valid virtual recipients
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| − | virtual_mailbox_maps = proxy:ldap:/etc/postfix/ldap_virtual_recipients.cf
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| − | | |
| − | # Virtual aliases
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| − | virtual_alias_maps = proxy:ldap:/etc/postfix/ldap_virtual_aliases.cf
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| − | | |
| − | | |
| − | ###################################################################################################
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| − | ### ESMTP Settings ###
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| − | ######################
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| − | | |
| − | ### SASL ###
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| − | | |
| − | # Enable SASL (required for SMTP authentication)
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| − | smtpd_sasl_auth_enable = yes
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| − | | |
| − | # Enable SASL for Outlook-Clients as well
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| − | broken_sasl_auth_clients = yes
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| − | | |
| − | ### TLS ###
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| − | | |
| − | # Enable TLS (required to encrypt the plaintext SASL authentication)
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| − | smtpd_tls_security_level = may
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| − | | |
| − | # Only offer SASL in a TLS session
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| − | smtpd_tls_auth_only = yes
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| − | | |
| − | # Certification Authority
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| − | smtpd_tls_CAfile = /etc/postfix/certs/example-cacert.pem
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| − | | |
| − | # Public Certificate
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| − | smtpd_tls_cert_file = /etc/postfix/certs/mail_public_cert.pem
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| − | | |
| − | # Private Key (without passphrase)
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| − | smtpd_tls_key_file = /etc/postfix/certs/mail_private_key.pem
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| − | | |
| − | # Randomizer for key creation
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| − | tls_random_source = dev:/dev/urandom
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| − | | |
| − | # TLS related logging (set to 2 for debugging)
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| − | smtpd_tls_loglevel = 0
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| − | | |
| − | # Avoid Denial-Of-Service-Attacks
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| − | smtpd_client_new_tls_session_rate_limit = 10
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| − | | |
| − | # Activate TLS Session Cache
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| − | smtpd_tls_session_cache_database = btree:/etc/postfix/smtpd_session_cache
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| − | | |
| − | # Deny some TLS-Ciphers
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| − | smtpd_tls_exclude_ciphers =
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| − | EXP
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| − | EDH-RSA-DES-CBC-SHA
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| − | ADH-DES-CBC-SHA
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| − | DES-CBC-SHA
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| − | SEED-SHA
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| − | | |
| − | # Diffie-Hellman Parameters for Perfect Forward Secrecy
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| − | # Can be created with:
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| − | # openssl dhparam -2 -out dh_512.pem 512
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| − | # openssl dhparam -2 -out dh_1024.pem 1024
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| − | smtpd_tls_dh512_param_file = ${config_directory}/certs/dh_512.pem
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| − | smtpd_tls_dh1024_param_file = ${config_directory}/certs/dh_1024.pem
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| − | | |
| − | | |
| − | ###################################################################################################
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| − | ### Connection Policies ###
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| − | ###########################
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| − | | |
| − | # Reject Early Talkers
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| − | postscreen_greet_action = enforce
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| − | | |
| − | | |
| − | ###################################################################################################
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| − | ### Session Policies ###
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| − | ########################
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| − | | |
| − | # Recipient Restrictions (RCPT TO related)
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| − | smtpd_recipient_restrictions =
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| − | # Allow relaying for SASL authenticated clients and trusted hosts/networks
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| − | # This can be put to smtpd_relay_restrictions in Postfix 2.10 and later
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| − | permit_sasl_authenticated
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| − | permit_mynetworks
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| − | reject_non_fqdn_recipient
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| − | reject_unknown_recipient_domain
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| − | reject_unauth_destination
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| − | # Reject the following hosts
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| − | check_sender_ns_access cidr:/etc/postfix/drop.cidr
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| − | check_sender_mx_access cidr:/etc/postfix/drop.cidr
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| − | # Additional blacklist
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| − | reject_rbl_client ix.dnsbl.manitu.net
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| − | # Finally permit (relaying still requires SASL auth)
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| − | permit
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| − | | |
| − | # Reject the request if the sender is the null address and there are multiple recipients
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| − | smtpd_data_restrictions = reject_multi_recipient_bounce
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| − | | |
| − | # Sender Restrictions
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| − | smtpd_sender_restrictions =
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| − | reject_non_fqdn_sender
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| − | reject_unknown_sender_domain
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| − | | |
| − | # HELO/EHLO Restrictions
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| − | smtpd_helo_restrictions =
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| − | permit_mynetworks
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| − | check_helo_access pcre:/etc/postfix/identitycheck.pcre
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| − | #reject_non_fqdn_helo_hostname
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| − | reject_invalid_hostname
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| − | | |
| − | # Deny VRFY recipient checks
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| − | disable_vrfy_command = yes
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| − | | |
| − | # Require HELO
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| − | smtpd_helo_required = yes
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| − | | |
| − | # Reject instantly if a restriction applies (do not wait until RCPT TO)
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| − | smtpd_delay_reject = no
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| − | | |
| − | # Client Restrictions (IP Blacklist)
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| − | smtpd_client_restrictions = check_client_access cidr:/etc/postfix/drop.cidr
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| − | </syntaxhighlight>
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| − | </div>
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| − | </div>
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| − | | |
| − | <div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
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| − | <code>virtual_domains</code> Innehåller vilka domäner server tar emot mail för.
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| − | <div class="mw-collapsible-content">
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| − | <syntaxhighlight lang=bash>#!/bin/bash
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| − | # Domain Anything
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| − | example.com OK
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| − | </syntaxhighlight>
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| − | </div>
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| − | </div>
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| − | | |
| − | <div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
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| − | <code>ldap_virtual_recipients.cf</code> LDAP fråga för att validera mottagaren.
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| − | <div class="mw-collapsible-content">
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| − | <syntaxhighlight lang=bash>#!/bin/bash
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| − | bind = yes
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| − | bind_dn = uid=postfix,ou=services,dc=example,dc=com
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| − | bind_pw = secret
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| − | server_host = ldap://127.0.0.1:389
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| − | search_base = ou=people,dc=example,dc=com
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| − | domain = example.com
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| − | query_filter = (&(mail=%s)(mailEnabled=TRUE))
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| − | result_attribute = mail
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| − | </syntaxhighlight>
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| − | </div>
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| − | </div>
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| − | <div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
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| − | <code>ldap_virtual_aliases.cf</code> LDAP fråga för att få fram aliases och forwarding adress.
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| − | <div class="mw-collapsible-content">
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| − | <syntaxhighlight lang=bash>#!/bin/bash
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| − | bind = yes
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| − | bind_dn = uid=postfix,ou=services,dc=example,dc=com
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| − | bind_pw = secret
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| − | server_host = ldap://127.0.0.1:389
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| − | search_base = ou=people,dc=example,dc=com
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| − | domain = example.com
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| − | query_filter = (&(mailAlias=%s)(mailEnabled=TRUE))
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| − | result_attribute = mail, email
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| − | </syntaxhighlight>
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| − | </div>
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| − | </div>
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| − | <div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
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| − | <code>identitycheck.pcre</code> Regexp för att blocka klienter som använder ditt hostnamn.
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| − | <div class="mw-collapsible-content">
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| − | <syntaxhighlight lang=bash>#!/bin/bash
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| − | # Identity (RegEx) Action
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| − | | |
| − | /^(mail\.example\.com)$/ REJECT Hostname Abuse: $1
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| − | /^(1\.2\.3\.4)$/ REJECT Hostname Abuse: $1
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| − | /^(\[1\.2\.3\.4\])$/ REJECT Hostname Abuse: $1
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| − | </syntaxhighlight>
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| − | </div>
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| − | </div>
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| − | <div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
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| − | <code>drop.cidr</code> Innehåller svartlistade IP-adresser.
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| − | <div class="mw-collapsible-content">
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| − | <syntaxhighlight lang=bash>#!/bin/bash
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| − | # IP/CIDR Action
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| − | | |
| − | 1.2.3.0/24 REJECT Blacklisted
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| − | </syntaxhighlight>
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| − | </div>
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| − | </div>
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| − | | |
| − | Temporärt kommentera ut följande rader eftersom att [[Dovecot]] och TLS inte är konfigurerat i main.cf:
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| − | *dovecot_destination_recipient_limit = 1
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| − | *smtpd_tls_security_level = may
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| − | *smtpd_tls_auth_only = yes
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| − | *smtpd_tls_CAfile = /etc/postfix/certs/example-cacert.pem
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| − | *smtpd_tls_cert_file = /etc/postfix/certs/mail_public_cert.pem
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| − | *smtpd_tls_key_file = /etc/postfix/certs/mail_private_key.pem
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| − | | |
| − | Skapa en postmap db fil för din domän.
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| − | postmap hash:/etc/postfix/virtual_domains
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| − | | |
| − | Starta postfix och anslut mot servern med telnet mot port 25. Prova att skicka <code>EHLO client</code>, då ska du få följande svar:
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| − | <syntaxhighlight lang=text>
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| − | Trying 127.0.0.1...
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| − | Connected to 127.0.0.1.
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| − | Escape character is '^]'.
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| − | 220 mail.example.com ESMTP Postfix (Ubuntu)
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| − | EHLO client
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| − | 250-mail.example.com
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| − | 250-PIPELINING
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| − | 250-SIZE 10240000
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| − | 250-ETRN
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| − | 250-AUTH DIGEST-MD5 NTLM CRAM-MD5 LOGIN PLAIN
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| − | 250-AUTH=DIGEST-MD5 NTLM CRAM-MD5 LOGIN PLAIN
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| − | 250-ENHANCEDSTATUSCODES
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| − | 250-8BITMIME
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| − | 250 DSN
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| − | QUIT
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| − | 221 2.0.0 Bye
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| − | </syntaxhighlight>
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| − | | |
| − | Testa att ställa en LDAP fråga.
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| − | postmap -q user@example.com ldap:/etc/postfix/ldap_virtual_recipients.cf
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| − | postmap -q postmaster@example.com ldap:/etc/postfix/ldap_virtual_aliases.cf
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| − | | |
| − | Båda frågorna bör ge user@example.com som svar.
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