Local SMTP Relay Server 2.4 serial key or number

Postfix is a free and open-sourcemail transfer agent (MTA) that routes and delivers electronic mail.

It is released under the IBM Public License 1.0 which is a free software license. Alternatively, starting with version 3.2.5, it is available under the Eclipse Public License 2.0 at the user's option.^[2]

Originally written in 1997 by Wietse Venema at the IBMThomas J. Watson Research Center in New York, and first released in December 1998^[3], Postfix continues as of 2020^[update] to be actively developed by its creator and other contributors. The software is also known by its former names VMailer and IBM Secure Mailer.

In August 2019 a study performed by E-Soft, Inc.,^[4] approximately 34% of the publicly reachable mail-servers on the Internet ran Postfix, making it the second most popular mail server behind Exim.

Typical deployment[edit]

As an SMTP server, Postfix implements a first layer of defense against spambots and malware. Administrators can combine Postfix with other software that provides spam/virus filtering (e.g., Amavisd-new), message-store access (e.g., Dovecot), or complex SMTP-level access-policies (e.g., postfwd, policyd-weight or greylisting).

As an SMTP client, Postfix implements a high-performance parallelized mail-delivery engine. Postfix is often combined with mailing-list software (such as Mailman).

Operating systems[edit]

Postfix runs (or has run) on AIX, BSD, HP-UX, Linux, macOS, Solaris and, generally speaking, on every Unix-like operating system that ships with a Ccompiler and delivers a standard POSIX development environment. It is the default MTA for the macOS, NetBSD^[5] and Ubuntu operating systems.^[6]

Architecture[edit]

Postfix consists of a combination of server programs that run in the background, and client programs that are invoked by user programs or by system administrators.

The Postfix core consists of several dozen server programs that run in the background, each handling one specific aspect of email delivery. Examples are the SMTP server, the scheduler, the address rewriter, and the local delivery server. For damage-control purposes, most server programs run with fixed reduced privileges, and terminate voluntarily after processing a limited number of requests. To conserve system resources, most server programs terminate when they become idle.

Client programs run outside the Postfix core. They interact with Postfix server programs through mail delivery instructions in the user's ~/.forward file, and through small "gate" programs to submit mail or to request queue status information.

Other programs provide administrative support to start or stop Postfix, query status information, manipulate the queue, or to examine or update its configuration files.

Yellow ellipses

One of Postfix' many daemons serving exactly one purpose. This split-up into many smaller pieces of software is considered one of the reasons why Postfix is secure and stable.

Blue boxes

The blue boxes represent so-called lookup tables. A lookup table consists of two columns (key and value) containing information used for access control, e-mail routing etc.

Yellow boxes

The yellow boxes are either mail queues or files. In either case, e-mails are stored on persistent media (e.g., a hard disk).

White clouds

The clouds stand for points at which e-mails enter or leave Postfix. For example, smtpd receives mail from other mail servers or users whereas smtp relays mail to other MTAs.

Implementation[edit]

The Postfix implementation uses safe subsets of the C language and of the POSIX system API. These subsets are buried under an abstraction layer that contains about 50% of all Postfix source code, and that provides the foundation on which all Postfix programs are built. For example, the "vstring" primitive makes Postfix code resistant to buffer overflow^[7] attacks, and the "safe open" primitive makes Postfix code resistant to race condition attacks on systems that implement the POSIX file system API. This abstraction layer does not affect the attack resistance of non-Postfix code, such as code in system libraries or in third-party libraries.

Robustness[edit]

Conceptually, Postfix manages pipelines of processes that pass the responsibility for message delivery and error notification from one process to the next. All message and notification "state" information is persisted in the file system. The processes in a pipeline operate mostly without centralized control; this relative autonomy simplifies error recovery. When a process fails before completing its part of a file or protocol transaction, its predecessor in the pipeline backs off and retries the request later, and its successor in the pipeline discards unfinished work. Many Postfix daemons can simply "die" when they run into a problem; they are automatically restarted when the next service request arrives. This approach makes Postfix highly resilient, as long as the operating system or hardware don't fail catastrophically.

Performance[edit]

One single Postfix instance has been clocked at ~300 message deliveries/second^[8] across the Internet, running on commodity hardware (a vintage-2003 Dell 1850 system with battery-backed MegaRAID controller and two SCSI disks). This delivery rate is an order of magnitude below the "intrinsic" limit of 2500 message deliveries/second^[8] that was achieved with the mail queue on a RAM disk while delivering to the "discard" transport (with a dual-core Opteron system in 2007).

Mail systems such as Postfix and Qmail achieve high performance by delivering mail in parallel sessions. With mail systems such as Sendmail and Exim that make one connection at a time, high performance can be achieved by submitting limited batches of mail in parallel, so that each batch is delivered by a different process. Postfix and Qmail require parallel submission into different MTA instances once they reach their intrinsic performance limit, or the performance limits of the hardware or operating system.

The delivery rates cited above are largely theoretical. With bulk mail delivery, the true delivery rate is primarily determined by the receiver's mail receiving policies and by the sender's reputation.

Base configuration[edit]

The main.cf file stores site-specific Postfix configuration parameters while master.cf defines daemon processes.^[9] The Postfix Basic Configuration tutorial covers the core settings that each site needs to consider, and the Postfix Standard Configuration Examples document discusses configuration settings for a few common environments. The Postfix Address Rewriting document covers address rewriting and mail routing. The full documentation collection is at Postfix Documentation

More complex Postfix implementations may include: integration with other applications such as SpamAssassin; support for multiple virtual domain names - and use databases such as MySQL to control complex configurations.

Release history[edit]

See also[edit]

References[edit]

Further reading[edit]

External links[edit]

Specifies the mail relay mode for the mail server.

If parameter is used, requires the opion.

To set the Plesk mail server relaying mode to “authorization is required” ():

To restrict the maximum message size that can be accepted by the mail server to 2 M:

To limit the number of concurrent connections to the mail server to 100:

To limit the number of concurrent connections to the mail server from a single IP address to 5:

To enable MAPS spam protection on the mail server:

To add domain names maps1.example.com and maps2.example.com to the MAPS spam protection list:

To enable MAPS spam protection for domain names maps1.example.com and maps2.example.com:

To remove domain names maps1.example.com and maps2.example.com from the MAPS spam protection list:

Specifies the mail user login name format for accessing mail accounts by means of the POP3 or IMAP protocols.

• - only login names in the <user@example.com> (the “full” format) are allowed
• - login names in both <user> (the “short” format) and <user@example.com> (the “full” format) are allowed

Is set to by default.

To allow using both the “short” and “full” login name formats for mail users to access their mail accounts by means of the POP3 or IMAP protocols on the mail server:

To enable checking of mail user passwords against the password dictionary to prevent users from setting simple passwords:

To add domain names example.org and sample.example.net to the black list of mail server:

To remove domain names sample.example.org and forum.example.net from the mail server black list:

To add 192.0.2.0/24 and 192.0.2.3/16 to the mail server white list:

To remove 192.0.2.0/24 and 192.0.2.4/16 from the mail server white list:

To enable the Odin Premium antivirus on the mail server:

Updates the Sender Policy Framework (SPF) settings.

Note: SPF cannot be disabled if DMARC spam protection is enabled.

To enable the SPF spam protection on the mail server:

Enables DMARC spam protection.

Note: This command can be used only if DKIM and SPF spam protection are enabled. Otherwise, the error message will be displayed.

To enable DMARC spam protection for incoming mail on the mail server:

To disable DMARC spam protection for incoming mail on the mail server:

To enable message submission on all IP addresses:

Allows/Prohibits using DKIM spam protection method to sign outgoing mail.

Is by default.

To enable signing of outgoing mail on the mail server:

Allows/Prohibits using DKIM spam protection method to verify incoming mail.

Is by default.

Note: DKIM cannot be disabled for incoming mail if DMARC spam protection is enabled.

To enable verifying incoming mail on the mail server:

Enables/Disables the selected webmail client.

Requires the option.

To enable Horde webmail on the mail server:

Displays mail server settings. The following modes are available:

• - displays various mail server settings except for the mail server black and white lists contents and the Sender Policy Framework (SPF) settings.
• - displays the mail server black list content
• - displays the mail server white list content
• - displays the SPF settings.
• - displays the webmail software used in Plesk and its status.

To view the SPF settings:

or

To remove the messages in the mail queue:

Registers an additional (external) webmail service with the Plesk so that you can provide your users with access to it.

Requires the and the options.

To learn more about registering additional webmail services with the Plesk, refer to Administrator’s Guide at http://docs.plesk.com/en-US/17.0/administrator-guide/mail/webmail-software

To register an external webmail service called ExampleMail at URL mail.example.com:

To change the URL for the webmail record ExampleMail to mail2.example.com:

To change the name for the external webmail service ExampleMail to SampleMail:

To remove the external webmail service record ExampleMail:

Updates the settings of an external SMTP server for outgoing mail.

Note that to use an external SMTP server, you should install a special client through Tools & Settings > Updates and Upgrades > Mail hosting features > Different mail servers.

To update the external SMTP server settings:

To turn on the usage of limitations on outgoing mail from the Plesk server:

To turn off the usage of limitations on outgoing mail from the Plesk server:

To set the default value for the limit on outgoing email messages from an email address:

To set the default value for the limit on outgoing email messages from a domain:

To set the default value for the limit on outgoing email messages from a subscription:

To prohibit PHP scripts send outgoing mail from the Plesk server using sendmail:

To make Plesk calculate reports on outgoing mail using the data for the last two weeks:

To make Plesk send notifications to administrator on outgoing mail every 6 hours:

If you use Postfix, you can set outgoing mail mode, which means IP addresses that Plesk uses to send mail from. By default, mail from each domain is sent using the domain’s IP address (the value).

If domain IP addresses are used to send mail, you can make Plesk use the domain names in SMTP greeting, by using the value.

If you need Plesk to send all mail from one IP address, use and corresponding options and

To make Plesk use domain names in SMTP greetings:

To make Plesk send all mail from the IP address 10.0.0.1:

To secure the mail server with the SSL/TLS certificate cert3 that is stored at the repository of the domain example.net:

Specifies the domain of the SSL/TLS certificate repository. By default, the server repository is used.

This option is used with the command .

To view the help on the use of the utility:

or

MailEnable Enterprise Edition
Configuration Guide
Version 1.0

MailEnable Messaging Services
for Microsoft Windows NT/2000/2003

Table of Contents

1Introduction to MailEnable Enterprise Edition. 6

1.1Contact the MailEnable Team.. 6

1.2How to Download MailEnable Enterprise. 6

1.3MailEnable Pre-requisite Hardware. 6

1.4MailEnable Pre-requisite Software. 7

2How Internet Email Works. 8

2.1Email Clients. 8

2.2Email Server8

2.3Sending and Receiving Mail8

3MailEnable Overview.. 9

3.1Structure of MailEnable. 9

3.2Administering MailEnable. 10

3.3Email delivery flow.. 12

4Installation. 13

4.1Installation Overview.. 13

4.2Welcome Screen. 13

4.3Terms and Conditions. 13

4.4Registration Details. 13

4.5Selecting Installation Components. 13

4.6Selecting Repository. 14

4.7Selecting Program Group. 14

4.8Selecting Configuration Repository Location. 14

4.9Creating an Initial Post Office. 15

4.10Selecting Message Store Repository Location. 15

4.11SMTP Connector Configuration. 16

4.12Start Installation. 17

4.13Database Schema Warning. 17

4.14Selecting Web Mail Web Site. 17

4.15Web Administration. 17

4.16Antivirus Plug-In Notice. 18

4.17HTTPMail Notice. 18

4.18Completing Installation. 19

5Upgrading. 20

6Post-Installation Configuration. 22

6.1MailEnable Diagnostic Utility. 22

6.2Check and Configure DNS Settings. 24

6.3Check and Configure Integrated Antivirus. 25

6.4Check and Configure Relay Settings. 26

6.5Check Mail Services. 28

7Administration. 29

7.1Overview.. 29

7.2Messaging Manager29

7.3Post Office Configuration. 31

7.4Post Office Actions. 35

7.5Lists. 44

7.6Server Configuration. 47

7.7Option Files. 49

8Configuration of Connectors, Services and Agents. 50

8.1SMTP. 50

8.2POP. 58

8.3POP Retrieval Connector60

8.4Post Office Connector61

8.5IMAP Service. 63

8.6HTTPMail Protocol65

8.7Mail Transfer Agent (MTA)67

8.8Web Mail68

8.9Web Administration. 75

8.10Management Agents. 79

8.11COM Component84

9Database Configuration Repository. 87

9.1Installing ODBC Driver87

9.2Initializing the Repository. 87

9.3Migrating Data between Providers. 88

10Remote Management91

11Message Filtering. 92

11.1MailEnable Global Message Filters. 92

11.2Creating a global filter100

11.3Mailbox filtering. 104

12Cluster Management106

13Configuration of Email Clients. 108

13.1Netscape Messenger108

13.2Microsoft Outlook Express. 108

13.3Microsoft Outlook. 108

13.4Mozilla Thunderbird. 109

13.5Configuring Clients for HTTPMail109

14Logical Architecture and Message Flow.. 113

15Operational Procedures. 116

15.1Backing Up and Restoring MailEnable Data. 116

15.2Debugging MailEnable. 116

15.3Inspecting Log Files. 116

15.4Licensing MailEnable. 117

16Appendix. 118

16.1Multiple Server Storage of MailEnable. 118

16.2Using your own Antivirus Scanner118

16.3Accessing Web Mail for Automatic Sign on. 119

16.4DNS Error codes and descriptions. 119

16.5Diagnosing Outlook/Outlook Express Error Codes. 120

16.6Manually testing if MailEnable can send mail to remote servers. 121

16.7Log Analyser123

16.8Antivirus configuration. 124

16.9IIS Configuration. 126

16.10Configuring redundant or backup (MX) mail servers. 127

16.11Increasing Upload Limit for Windows 2003. 127

16.12Activity Monitor128

16.13MEInstaller128

17Glossary. 130

Warranty

You should carefully read the following terms and conditions before using this software.Unless you have a different license agreement signed by the respective owners, authors and copyright holders of the MailEnable product suite, herewith referred to as ("ME"), your use, distribution, or installation of this copy of MailEnable indicates your acceptance of this License.

All rights of any kind in MailEnable which are not expressly granted in this License are entirely and exclusively reserved to and by "ME". You may not rent, lease, modify, reverse engineer, translate, decompile and disassemble MailEnable without the permission of its owners, authors and copyright holders of MailEnable.

You are not permitted to commercialize derivative works of MailEnable without a written agreement signed by the respective owners, authors and copyright holders of MailEnable.

All accompanying files, data and materials, are distributed "as is" and with no warranties of any kind, whether express or implied.

This disclaimer of warranty constitutes an essential part of the agreement. Any liability of "ME" will be limited exclusively to refund of purchase price. In no event shall "ME", including but not limited to its principals, shareholders, officers, employees, affiliates, contractors, subsidiaries, or parent organizations, be liable for any incidental, consequential, or punitive damages whatsoever relating to the use of MailEnable, or your relationship with "ME".

In addition, in no event does "ME" authorize you to use MailEnable in applications or systems where "ME"'s failure to perform can reasonably be expected to result in a significant physical injury, or in loss of life.Any such use by you is entirely at your own risk, and you agree to hold "ME" harmless from any claims or losses relating to such unauthorized use.

You are specifically prohibited from charging, or requesting donations, for any copies, however made, and from distributing such copies with other products of any kind, commercial or otherwise, without prior written permission from "ME". "ME" reserves the right to revoke the above distribution rights at any time, for any or no reason.

1.1                  Contact the MailEnable Team

MailEnable Pty. Ltd. (ACN 100 453 674) is an Internet Messaging product company that develops, markets and supports software for hosted messaging solutions. MailEnable’s mail server suite provides a tightly integrated hosted messaging solution for the Microsoft platform.

MailEnable is a 100% privately owned Australian Company and was established in early 2001. MailEnable's customers include some of the worlds largest Internet/Application Service Providers, Educational Institutions, Organizations, Government Agencies and Corporates.

486 Neerim Road
Murrumbeena, 3163
Victoria, Australia
Tel:+613 9563-4177 (AEST)
Fax:+613 9530-4066
Email: info@mailenable.com

1.1.1              Support Contact

For any support issues including program defects and general support inquiries, please follow the link below.The web page displayed here shows a form, which once correctly filled out, will permit the MailEnable support team to assist in any support requests.

http://www.mailenable.com/support/supportrequest.asp

1.1.1.1