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°Sendmail server configuration
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Postfix is infinitely configurable to suit your needs. For
large corporations and
ISPs, Postfix can be configured to use a mySQL backend instead of using
configuration files. Thus a quick insert or delete of a record can add
users, domains, etc. This tutorial configures Postfix to receive email
using local configuration files.
Postfix configuration file: /etc/postfix/main.cf
(Red Hat, Fedora, Suse and Ubuntu!)
Basic:
-
# Common for all Postfix configurations:
smtpd_banner = $myhostname ESMTP $mail_name
biff = no
mailbox_size_limit = 0
recipient_delimiter = +
append_dot_mydomain = no
mail_spool_directory = /var/mail
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Allow no relay or outbound SMTP:
-
Add to file main.cf:
relayhost =
mynetworks = 127.0.0.1/32
inet_interfaces = all
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Receive email for local users: (multiple domains can be
specified but an email sent to Michael is not distinguished between
domains. One Michael for all domains.)
-
Add to file main.cf:
myhostname = mail.megawebhost.com
mydomain = megawebhost.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
# All domains listed in mydestination are subject to /etc/aliases mapping.
# Do not list domains to be used with virtual hosts!
mydestination = $mydomain $myhostname alternateName1 localhost.localdomain localhost
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Virtual host:
(receive email for multiple domains. Users distinguished between domains.
Email recipient ed@megacorp.com is different than ed@charity.com)
Add this definition to support virtual hosts:
-
Add to file main.cf:
# After edting file /etc/postfix/valias.txt
# run command: postmap /etc/postfix/valias.txt
# to create hash db file.
virtual_alias_maps = hash:/etc/postfix/valias.txt
# Use local unix account mailboxes for these domains
virtual_alias_domains = /etc/postfix/vhosts.txt
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Add anti-SPAM measures:
-
Add to file main.cf:
# Place all of the restrictions into the smtpd_recipient_restrictions:
smtpd_client_restrictions =
smtpd_helo_restrictions =
smtpd_sender_restrictions =
smtpd_helo_required = yes
strict_rfc821_envelopes = yes
disable_vrfy_command = yes
unknown_address_reject_code = 554
unknown_hostname_reject_code = 554
unknown_client_reject_code = 554
smtpd_recipient_restrictions =
# permit_mynetworks,
# permit_sasl_authenticated,
reject_unauth_destination,
reject_invalid_hostname,
reject_unauth_pipelining,
reject_non_fqdn_hostname,
reject_non_fqdn_sender,
reject_non_fqdn_recipient,
reject_unknown_sender_domain,
reject_unknown_recipient_domain,
# check_client_access hash:/etc/postfix/maps/access_client,
# check_helo_access hash:/etc/postfix/maps/access_helo,
# check_sender_access hash:/etc/postfix/maps/access_sender,
check_sender_access hash:/etc/postfix/access_sender,
# check_recipient_access hash:/etc/postfix/maps/access_recipient,
reject_rhsbl_client blackhole.securitysage.com,
reject_rhsbl_sender blackhole.securitysage.com,
# reject_rbl_client relays.ordb.org, THIS SITE IS RETIRED
reject_rbl_client blackholes.easynet.nl,
reject_rbl_client cbl.abuseat.org,
# reject_rbl_client proxies.blackholes.wirehub.net, THIS SITE IS RETIRED
reject_rbl_client bl.spamcop.net,
reject_rbl_client zen.spamhaus.org,
reject_rbl_client opm.blitzed.org,
reject_rbl_client dnsbl.njabl.org,
reject_rbl_client list.dsbl.org,
reject_rbl_client multihop.dsbl.org,
reject_rbl_client dul.dnsbl.sorbs.net,
permit
smtpd_data_restrictions =
reject_unauth_pipelining,
permit
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Note:
- SpamHaus combines three blackhole lists: Exploits block list (exploited systems): xbl.spamhaus.org, Policy block list (non-MTA IP): pbl.spamhaus.org and Spamhaus block list: sbl.spamhaus.org, into one "zen.spamhaus.org".
File: /etc/postfix/vhosts.txt
-
megacorp.com
charityX.org
productX.com
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Domains listed here should NOT be listed with the "mydestination" directive.
File: /etc/postfix/valias.txt
-
This file maps email addresses to local user names:
joe@megacorp.com userjoe
joe@charityX.org userjoseph
info@productX.com userjoe
|
Upon creation or change, create the db file: postmap /etc/postfix/valias.txt
This creates the file /etc/postfix/valias.txt.db
File: /etc/postfix/access_sender
-
0.0.0.0/8 REJECT Domain MX in broadcast network
10.0.0.0/8 REJECT Domain MX in RFC 1918 private network
127.0.0.0/8 REJECT Domain MX in loopback network
169.254.0.0/16 REJECT Domain MX in link local network
172.16.0.0/12 REJECT Domain MX in RFC 1918 private network
192.0.2.0/24 REJECT Domain MX in TEST-NET network
192.168.0/16 REJECT Domain MX in RFC 1918 private network
224.0.0.0/4 REJECT Domain MX in class D multicast network
240.0.0.0/5 REJECT Domain MX in class E reserved network
248.0.0.0/5 REJECT Domain MX in reserved network
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Postfix configuration tutorials:
More examples:
| Postfix and Mailman email list server integration and configuration: |
Postfix can be configured three different ways to interface with Mailman.
The following uses the /etc/aliases file for this configuration.
Requires the following main.cf configuration:
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
File: /etc/aliases
-
#
# regular aliases
#
info: user1
joe: user1
theadore: ted
#
# mailman aliases
#
mailman: "|/var/mailman/mail/mailman post mailman"
mailman-admin: "|/var/mailman/mail/mailman admin mailman"
mailman-bounces: "|/var/mailman/mail/mailman bounces mailman"
mailman-confirm: "|/var/mailman/mail/mailman confirm mailman"
mailman-join: "|/var/mailman/mail/mailman join mailman"
mailman-leave: "|/var/mailman/mail/mailman leave mailman"
mailman-owner: "|/var/mailman/mail/mailman owner mailman"
mailman-request: "|/var/mailman/mail/mailman request mailman"
mailman-subscribe: "|/var/mailman/mail/mailman subscribe mailman"
mailman-unsubscribe: "|/var/mailman/mail/mailman unsubscribe mailman"
#
megacorp: "|/var/mailman/mail/mailman post megacorp"
megacorp-admin: "|/var/mailman/mail/mailman admin megacorp"
megacorp-bounces: "|/var/mailman/mail/mailman bounces megacorp"
megacorp-confirm: "|/var/mailman/mail/mailman confirm megacorp"
megacorp-join: "|/var/mailman/mail/mailman join megacorp"
megacorp-leave: "|/var/mailman/mail/mailman leave megacorp"
megacorp-owner: "|/var/mailman/mail/mailman owner megacorp"
megacorp-request: "|/var/mailman/mail/mailman request megacorp"
megacorp-subscribe: "|/var/mailman/mail/mailman subscribe megacorp"
megacorp-unsubscribe: "|/var/mailman/mail/mailman unsubscribe megacorp"
#
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These entries are generated by Mailman. See the
YoLinux Mailman tutorial.
Links on Postfix and Mailman integration:
(Three different methodologies)
- Mailman configuration: part 1 -
part2 -
part3 (virtual hosts)
- Use regular expression in configuration: Nezo.net: example and tutorial.
Example configuration including apache
- Python script to glue Postfix and Mailman together for
domain "lists.example.com". This method does not require the creation
of aliases.:
| Postfix post-configuration and test: |
Check if an open relay: (you do not want to be an open relay)
 Books: |
-
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"Postfix"
by Richard Blum
ISBN #0672321149, Sams
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|
 |
"Linux Email"
by Black, Koetter, Hilderbrandt, McDonald, Rusenko and Taylor.
ISBN #190481137X, Packt
I reviewed this book and found it to be a very
complete discussion with examples of the installation, configuration,
integration and use of Postfix, Courier POP/IMAP, SquirelMail,
SpamAssassin, ClamAV and Cyrus SASL. It is concise and to the point.
How to configure a Linux email server for the most popular and useful
server configurations. This book is specific to the components listed
and will get you up and running fast.
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"Stopping Spam"
by Alan Schwartz, Debby Russell (Editor), Simson Garfinkel
ISBN #156592388X, O'Reilly and Associates
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"Removing the Spam : Email Processing and Filtering"
by Geoff Mulligan
ISBN #0201379570, Addison-Wesley Networking Basics Series
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