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Comparison of mail servers

{{short description|None}}

The comparison of mail servers covers mail transfer agents (MTAs), mail delivery agents, and other computer software that provide e-mail services.

Unix-based mail servers are built using a number of components because a Unix-style environment is, by default, a toolbox{{Cite web|first=Michael S.|last=Mahoney|url=https://www.princeton.edu/~hos/Mahoney/expotape.htm|title=The Unix Oral History Project: Release.0, The Beginning|url-status=live|archive-url=https://web.archive.org/web/20100119062927if_/http://www.princeton.edu/~hos/Mahoney/expotape.htm|archive-date=2010-01-19|language=en|df=mdy-all|quote=To me one of the lovely features of pipes is the way it reinforces the notion of toolbox…}} operating system. A stock Unix-like server already has internal mail; more traditional ones also come with a full MTA already part of the standard installation. To allow the server to send external emails, an MTA such as Sendmail, Postfix, or Exim is required. Mail is read either through direct access (shell login) or mailbox protocols like POP and IMAP. Unix-based MTA software largely acts to enhance or replace the respective system's native MTA.

Microsoft Windows servers do not natively implement e-mail, thus Windows-based MTAs have to supply all the necessary aspects of e-mail-related functionality.

Feature comparison

{{sticky header}}

{{sort-under}}

class="wikitable sortable sort-under sort-underfilterable sticky-header-multi" style="font-size: 85%; text-align: center;"
| {{Sort|00000
}

! colspan="3" | {{Sort|00000|OS support}}

! colspan="7" | {{Sort|00000|Protocol support}}

! colspan="7" | {{Sort|00000|Features}}

! colspan="2" | {{Sort|00000|Storage}}

! rowspan="2" | License

|-

! class="filterable" | Mail server

! Linux/Unix

! Windows

! macOS

! SMTP

! POP3

! IMAP

! JMAP

! IDLE

! SMTPS

! POP3S

! IPv6

! SSL

! DANE

! Webmail

! ActiveSync

! Sieve

! IDN/UTF8

! Database

! File-based

|-

|{{rh}}| agorum core

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{No}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{no}}

| {{Dunno}}

| {{yes}}

| {{no}}

| {{Open source|GPLv2}}

|-

|{{rh}}| Apache James

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{no}}

| {{no}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{open source|ASLv2}}

|-

|{{rh}}| Axigen

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes|Ajax, Basic & Mobile}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Yes|Embedded, Optimized for Email & Groupware}}

| {{yes}}

| {{Proprietary}} (free version: 5 domains, 5 users, 5 groups)

|-

|{{rh}}| Citadel

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{no}}

| {{open source|GPLv3}}

|-

|{{rh}}| CommuniGate Pro

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Proprietary}} (Free for up to 5 users)

|-

|{{rh}}| Courier Mail Server

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{no|maildrop}}

| {{yes}}

| {{no}}

| {{yes|maildir}}

| {{Open source|GPLv3+}}{{Cite web|date=2013-08-19|title=COPYING|url=https://github.com/svarshavchik/courier-libs/blob/678e4860457b742c8d12aa820cabb3cf4b6024bd/common/COPYING|url-status=live|access-date=2022-02-26|website=GitHub: svarshavchik/courier-libs|language=en|df=mdy-all|quote=This software is released under the GPL, version 3 (see COPYING.GPL).|archive-url=https://web.archive.org/web/20220226043302/https://github.com/svarshavchik/courier-libs/blob/678e4860457b742c8d12aa820cabb3cf4b6024bd/common/COPYING |archive-date=2022-02-26 }}

|-

|{{rh}}| Cyrus IMAP

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}{{Cite web|title=RFCs Supported by Cyrus IMAP|url=https://www.cyrusimap.org/imap/rfc-support.html#rfc-wishlist|access-date=2021-04-27|website=Cyrus IMAP 3.4.3 (stable) documentation}}

| {{Yes|Indexes only}}

| {{Yes}}

| {{Open source|BSD 4-clause}}{{Cite web|url=https://www.cyrusimap.org/imap/download/getcyrus.html#licensing|title=Get Cyrus|website=Cyrus IMAP 3.4.3 (stable) documentation|access-date=2022-02-25|archive-url=https://web.archive.org/web/20170722061226if_/https://www.cyrusimap.org/imap/download/getcyrus.html#licensing|archive-date=2017-07-22|url-status=live|language=en|df=mdy-all}}

|-

|{{rh}}| DBMail

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{Open source|GPLv2}}

|-

|{{rh}}| Dovecot

| {{yes}}[http://wiki.dovecot.org/OSCompatibility Dovecot Operating System Compatibility]. Retrieved on 2008-09-03.

| {{no}}

| {{yes}}

| {{yes}}[https://wiki2.dovecot.org/Submission Dovecot Submission Service]. Retrieved on 2010-07-15.

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes|maildir, mbox, dbox, mdbox, obox{{cite web|url=https://doc.dovecot.org/configuration_manual/mail_location/obox/|title=Dovecot Object Storage support|access-date=2021-01-25}}}}

| {{Open source|Mixed: MIT and LGPL-2.1}}{{cite web|url=http://www.dovecot.org/doc/COPYING|title=Dovecot licensing information: COPYING|access-date=2008-09-03}}

|-

|{{rh}}| Eudora Internet Mail Server

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{dunno}}

| {{no}}

| {{no}}

| {{dunno}}

| {{Dunno}}

| {{no}}

| {{no}}

| {{Proprietary}}

|-

|{{rh}}| Exim

| {{yes}}

| {{yes}} (via Cygwin)

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}{{cite web|url=http://www.exim.org/exim-html-current/doc/html/spec_html/ch-encrypted_smtp_connections_using_tlsssl.html#SECDANE |title=Exim 4.91 spec: Encrypted SMTP connections using TLS/SSL / 15. DANE|publisher=exim.org |access-date=2018-07-05}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{open source|GPLv2+}}See NOTICE file in the distribution

|-

|{{rh}}| FirstClass

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Gordano Messaging Suite

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{no}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| GroupWise

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{no}}

| {{Proprietary}}

|-

|{{rh}}| Halon

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}{{cite web|url=http://wiki.halon.io/DANE |title=Halon DANE support |publisher=Halon Security AB |access-date=2015-12-17}}{{Self-published source|date=April 2018|ABOUTSELF=y}}

| {{no}}

| {{no}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Haraka

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{no}}

| {{no}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{open source|MIT}}

|-

|{{rh}}|hMailServer

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{yes}}

| {{open source|GNU AGPL}}

|-

|{{rh}}| HCL Domino

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}} {{Cite web|title=Using HCL Traveler |url=https://help.hcltechsw.com/traveler/12.0.2/LNT_overview.html|access-date=2022-11-17|website=HCL Traveler documentation}}

| {{no}}

| {{Yes}}

| {{yes}}

| {{no}}

| {{Proprietary}}

|-

|{{rh}}| IceWarp Mail Server

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Ipswitch IMail Server

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}} (since v12.2){{cite web|url=https://docs.ipswitch.com/_Messaging/IMailServer/v12.2/ReleaseNotes/|title=IMail v12.2 Release Notes|website=docs.ipswitch.com}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{Dunno}}

| {{no}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Kerio Connect

| {{yes}}

| {{Yes}}

| {{Yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{no}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Kolab

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{open source|GPLv3}}

|-

|{{rh}}| Kopano

| {{yes}}

| {{no}}

| {{no}}

| {{no|postfix, etc.[http://doc.zarafa.com/trunk/Administrator_Manual/en-US/html/_architecture.html Zarafa Collaboration Platform architecture diagram]. Retrieved on 2011-12-10.}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no|postfix}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no|postfix}}

| {{yes}}

| {{no|z-push}}

| {{no}}

| {{yes}}

| {{yes|SQL}}

| {{yes}}

| {{open source|AGPLv3, paid}}{{cite web|url=https://kopano.com/pricing/|title=Kopano Pricing - Subscription Plans - Kopano Partners}}

|-

|{{rh}}| KumoMTA

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes|Lua}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{open source|ASLv2}}

|-

|{{rh}}| Mailsite

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Mailtraq

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| MDaemon

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{Partial|Not IMAP}}

| {{no}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Mercury Mail Transport System

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{Proprietary|Proprietary donationware}}

|-

|{{rh}}| Microsoft Exchange Server

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}{{cite web|url=https://technet.microsoft.com/en-us/library/cc540463(EXCHG.80).aspx|title=Microsoft Exchange Server 2007 RFC and Support for Standards: Exchange 2007 Help|last=Archiveddocs|website=technet.microsoft.com|date=23 January 2017 }}{{cite web|url=https://technet.microsoft.com/en-us/library/ff848256.aspx|title=Exchange 2010 Support for RFC Standards: Exchange 2010 Help|last=Archiveddocs|website=technet.microsoft.com|date=23 July 2014 }}

| {{yes}}

| {{yes}}

| {{yes}} {{cite web|url=https://technet.microsoft.com/en-us/library/bb629624(EXCHG.80).aspx|title=IPv6 Support in Exchange 2007 SP1 and SP2: Exchange 2007 Help|last=Archiveddocs|website=technet.microsoft.com|date=23 January 2017 }}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes2}} 3rd Party support

| {{Partial|Not IMAP}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| NetMail

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{no}}

| {{Proprietary}}

|-

|{{rh}}| OpenSMTPD

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}{{cite web|url=https://www.opensmtpd.org/presentations/eurobsdcon2017-smtpd/eurobsdcon2017-opensmtpd.pdf |title=OpenSMTPD, current state of affairs: Lookup layer change |publisher=OpenBSD.org |access-date=2018-07-24}}{{Self-published source|date=September 2017|ABOUTSELF=y}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{Yes|via custom backends}}

| {{Yes}}

| {{Open source|ISC}}

|-

|{{rh}}| Open-Xchange

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{no}}

| {{Proprietary|Proprietary/SaaS,
with open-source parts}}{{cite web|url=https://www.open-xchange.com/en/licenses-ox-app-suite|title=Licenses-OX-APP-Suite - Open-Xchange|website=www.open-xchange.com|access-date=2016-02-24|archive-date=2016-03-03|archive-url=https://web.archive.org/web/20160303023145/https://www.open-xchange.com/en/licenses-ox-app-suite|url-status=dead}}

|-

|{{rh}}| Oracle Communications Messaging Server

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Postfix

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{Yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{open source|IBM Public License}}

|-

|{{rh}}| qmail

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| with {{nowrap|ucspi-ssl,}} with patch

| with {{nowrap|ucspi-ssl}}

| {{nowrap|s/qmail}}, via Qsmtp

| with {{nowrap|ucspi-ssl,}} with patch

| {{nowrap|s/qmail}}

| {{no}}

| {{no}}

| {{no}}

| {{nowrap|s/qmail}}

| {{yes|(cdb)}}

| {{yes}}

| {{open source|Public domain}}

|-

|{{rh}}| Qpopper

| {{yes}}

| {{yes}} (via Cygwin)

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{no}}

| {{no}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{dunno}}

| {{no}}

| {{no}}

| {{dunno}}

| {{Dunno}}

| {{no}}

| {{yes}}

| {{Open source|[https://web.archive.org/web/20130221075156if_/http://www.eudora.com/products/unsupported/qpopper/license.html BSD-style]
(GPL-incompatible)}}Contains jurisdiction selection and IPL-style indemnification clause.

|-

|{{rh}}| Scalix

| {{yes}}

| {{No}}

| {{No}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}} (via Stunnel)

| {{yes}} (via Stunnel)

| {{dunno}}

| {{yes}} (via Stunnel)

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{dunno|Proprietary with OSS parts,
a community (Freeware)
and 3 paid editions
(SMB, Enterprise, Hosting)}}

|-

|{{rh}}| Sendmail

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}} (since 8.16)[https://fossies.org/linux/sendmail/RELEASE_NOTES Sendmail Release Notes]. Retrieved on 2021-01-08.

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{Dunno}}

| {{yes}}

| {{Open source|[https://ftp.sendmail.org/LICENSE Sendmail License]}}

|-

|{{rh}}| SparkEngine

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{no}}

| {{Dunno}}

| {{yes}}

| {{dunno}}

| {{no}}

| {{no}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| UW IMAP

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| WebPine

| {{no}}

| {{no}}

| {{Dunno}}

| {{yes}} (Indexes)

| {{yes}}

| {{open source|Apache License 2.0}}{{cite web|url=http://www.washington.edu/imap/documentation/SSLBUILD.html|title=UW IMAP software--UW IMAP Server Documentation|website=www.washington.edu}}

|-

|{{rh}}| WinGate

| {{no}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{Dunno}}

| {{no}}

| {{yes}}

| {{Proprietary}}

|-

|{{rh}}| Zarafa

| {{yes}}

| {{no}}

| {{no}}

| {{no|postfix etc.[http://doc.zarafa.com/trunk/Administrator_Manual/en-US/html/_architecture.html Zarafa Collaboration Platform architecture diagram]. Retrieved on 2011-12-10.}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no|postfix}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no|postfix}}

| {{yes}}

| {{no|z-push}}

| {{no}}

| {{no}}

| {{yes|SQL}}

| {{yes}}

| {{open source|AGPLv3, paid}}

|-

|{{rh}}| Zentyal

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{Dunno}}

| {{yes}}

| {{yes}}

| {{Proprietary|Proprietary, 45-day trial}}

|-

|{{rh}}| Zimbra

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{Dunno|ZPL and proprietary editions}}{{Cite web|url=https://www.zimbra.com/legal/licensing/|title=Licenses and Terms of Use|website=www.zimbra.com|url-status=live|archive-url=https://web.archive.org/web/20140901211205if_/http://www.zimbra.com/legal/licensing|archive-date=2014-09-01|access-date=2022-02-25|language=en|df=mdy-all}}

|-

! class="filterable"|Mail server

! Linux/Unix

! Windows

! macOS

! SMTP

! POP3

! IMAP

! JMAP

! IDLE

! SMTPS

! POP3S

! IPv6

! SSL

! DANE

! Webmail

! ActiveSync

! Sieve

! IDN/UTF8

! Database

! File-based

! License

|}

Authentication

{{sticky header}}

{{sort-under}}

style="font-size: 85%; text-align: center;" class="wikitable sortable sort-under sort-understicky-header"
Mail server

! {{verth|va=middle|SMTP AUTH}}

! {{verth|va=middle|POP before SMTP}}

! {{verth|va=middle|APOP}}

! {{verth|va=middle|File System}}

! {{verth|va=middle|Database}}

! {{verth|va=middle|LDAP}}

! {{verth|Native
Anti Hammer-Brute-force attack
protection}}

! Other

{{rh}}| agorum core

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{dunno}}

| PLAIN, LOGIN, CRAM-MD5,[https://tools.ietf.org/html/draft-ietf-sasl-crammd5-to-historic-00 CRAM-MD5 to Historic, 20 November 2008]. NTLM

{{rh}}| Apache James

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| PLAIN, LOGIN

{{rh}}| Axigen

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| GSSAPI, CRAM-MD5, DIGEST-MD5,[https://tools.ietf.org/html/rfc6331 Moving DIGEST-MD5 to Historic, July 2011]. APOP, CLRTXT, LOGIN, PLAIN, LDAP, Internal

{{rh}}| CommuniGate Pro

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Active Directory (LDAP), CLRTXT, CRAM-MD5, DIGEST-MD5, APOP, GSSAPI, NTLM, MSN, SESSIONID, External Authentication Plug-in. Also supports X.509 PKI auth via STARTTLS/SSL

{{rh}}| Courier Mail Server

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Managed by [http://www.courier-mta.org/authlib/ Courier authentication library] which can use PAM, Userdb, PostgreSQL(beta), MySQL, LDAP, and EXTERNAL.

{{rh}}| Cyrus IMAP

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Supports X.509 PKI auth via STARTTLS and EXTERNAL. Uses Cyrus SASL authentication library for support for other mechanisms: Berkeley DB, GDBM, or NDBM (sasldb), PAM, MySQL, PostgreSQL, SQLite, LDAP, Active Directory(LDAP), DCE, Kerberos 4 and 5, proxied IMAP auth, getpwent, shadow, SIA, Courier Authdaemon, httpform, APOP and SASL mechanisms: ANONYMOUS, CRAM-MD5, DIGEST-MD5, SCRAM-SHA-1(-PLUS), SCRAM-SHA-224(-PLUS), SCRAM-SHA-256(-PLUS), SCRAM-SHA-384(-PLUS), SCRAM-SHA-512(-PLUS), EXTERNAL, GSSAPI, LOGIN, NTLM, OTP, PASSDSS, PLAIN, SRP

{{rh}}| DBMail

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| LOGIN, Active Directory, OpenLDAP

{{rh}}| Dovecot

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Submission service supports SMTP AUTH. Offers SASL to MTAs.{{cite web|url=http://wiki.dovecot.org/DovecotFeatures|title=DovecotFeatures - Dovecot Wiki|website=wiki.dovecot.org}}{{cite web|url=http://wiki.dovecot.org/Authentication|title=Authentication - Dovecot Wiki|website=wiki.dovecot.org}} POP-before-SMTP via DRAC plugin. PAM, MySQL, PostgreSQL, SQLite, LDAP, Active Directory(LDAP), Kerberos 5, proxied IMAP auth, getpwent, shadow, SIA, BSDauth, Vpopmail. APOP and SASL mechanisms: ANONYMOUS, PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, SCRAM-SHA-1, EXTERNAL, GSSAPI, NTLM, OTP, SKEY, RPA.

{{rh}}| Eudora Internet Mail Server

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| CRAM-MD5, DIGEST-MD5, PLAIN, LOGIN

{{rh}}| Exim

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Cyrus SASL, Dovecot SASL, GNU SASL, CRAM-MD5, Heimdal GSSAPI, PLAIN, LOGIN, SPA

{{rh}}| FirstClass

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

|

{{rh}}| Gordano Messaging Suite

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{dunno}}

| PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, APOP, ODBC, Active Directory, NT Domain

{{rh}}| GroupWise

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| eDirectory, Any LDAPv3-compliant source

{{rh}}| Halon

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Many mechanism (SMTP callout, Dovecot SASL, REST, etc.) via script.{{cite web |url=http://wiki.halon.se/HSL |publisher=Halon Security AB |access-date=2016-02-11 |title=HSL - Halon SMTP server}}

{{rh}}| Haraka

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Proxy to other server, any other mechanism via AUTH plugins.

{{rh}}| HCL Domino

| {{yes}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}{{cite web|url=https://help.hcl-software.com/domino/14.0.0/admin/secu_using_internet_password_lockout.html|title=HCL Domino Documentation - Using Internet password lockout|date=30 June 2024|website=help.hcl-software.com}}

| Passkeys, Time-based one-time password

{{rh}}| IceWarp Mail Server

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| PLAIN, LOGIN, CRAM-MD5, NTLM

{{rh}}| Ipswitch IMail Server

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| Active Directory, Windows authentication, CRAM-MD5, PLAIN, LOGIN

{{rh}}| Kolab

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Kolab employs Cyrus and Postfix and thus supports all Cyrus SASL authentication methods and X.509 PKI auth via STARTTLS and EXTERNAL.

{{rh}}| Mailsite

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| NT Domain, Active Directory, PLAIN, LOGIN, NTLM, SCRAM-MD5, CRAM-MD5

{{rh}}| Mailtraq

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| NT Domain, Active Directory, Local Directory

{{rh}}| MDaemon

| {{yes}}

| {{no}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

|

{{rh}}| Mercury Mail Transport System

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{dunno}}

| Internal, LOGIN, PLAIN, CRAM-MD5, Netware, LDAP?, partial NT Domain

{{rh}}| Microsoft Exchange Server

| {{yes}}

| {{dunno}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| Active Directory, LOGIN,{{cite web|url=http://support2.gwava.com/kb/?View=entry&EntryID=1605|title=How to Configure Exchange to Allow AUTH LOGIN to work|website=support2.gwava.com}} NTLM

{{rh}}| NetMail

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| eDirectory, LDAP

{{rh}}| Oracle Communications Messaging Server

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Plain, Login, CRAM-MD5, DIGEST-MD5, Certificate

{{rh}}| OpenSMTPD

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| By default PLAIN and LOGIN over SSL only, Certificates, bsd_auth and PAM. Supports adding new authentication mechanisms through custom backends.

{{rh}}| Postfix

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{Yes}}

| Supports all Cyrus SASL authentication methods except for APOP.

{{rh}}| Qpopper

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Pluggable Authentication Modules, GSSAPI, CRAM-MD5, DIGEST-MD5, APOP, PLAIN, LDAP, [https://web.archive.org/web/20110303094032/http://asg.web.cmu.edu/sasl/ CMU SASL library], Kerberos

{{rh}}| qmail

| {{yes|with patch, {{nowrap|s/qmail}}}}

| {{yes|with vpopmail}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Works with any checkpassword utility. The original supports only LOGIN and PLAIN. Alternate checkpassword utilities support authentication against PAM, LDAP, and databases.

{{rh}}| Scalix

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Internal, LOGIN, PLAIN, X.500 (DAP), LDAP, OpenLDAP, Active Directory, eDirectory, Kerberos, etc.

{{rh}}| Sendmail

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Supports all Cyrus SASL authentication methods except for APOP. Also supports X.509 PKI auth via STARTTLS and EXTERNAL.

{{rh}}| WinGate

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{dunno}}

| NT Domain, Active Directory, CRAM-MD5, SASL PLAIN, SASL LOGIN

{{rh}}| Zarafa

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| PLAIN, LOGIN using internal backends: Internal, Active Directory, any LDAP-compatible source, Unix

{{rh}}| Zentyal

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Active Directory using Dovecot SASL mechanisms

{{rh}}| Zimbra

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| Internal, LDAP, Open LDAP, Active Directory

Mail server

! {{verth|va=middle|SMTP AUTH}}

! {{verth|va=middle|POP before SMTP}}

! {{verth|va=middle|APOP}}

! {{verth|va=middle|File System}}

! {{verth|va=middle|Database}}

! {{verth|va=middle|LDAP}}

! {{verth|Native
Anti Hammer-Brute-force attack
protection}}

! Other Authentication possibilites

Antispam features

{{sticky header}}

class="wikitable sortable sort-under sort-understicky-header" style="font-size: 85%; text-align: center;"

! Mail Server

! DNSBL

! SURBL

! Spamtraps

! Greylisting

! SPF

! DKIM

! DMARC

! Tarpit

! Bayesian filters

! Regular expressions

! Embedded Antivirus

! Embedded Antispam

{{rh}}| agorum core

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{no}}

| {{yes}}

| {{no}}

| {{no}}

{{rh}}| Apache James

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{dunno}}

| {{yes}} ClamAV{{cite web |url=http://james.apache.org/server/3/dev-provided-mailets.html#ClamAVScan |title=Documentation for built-in ClamAV-Mailet |access-date=2013-03-19}}

| {{optional}} (Apache SpamAssassin)

{{rh}}| Axigen

| {{yes}}

| {{No}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}, in SpamAssassin

| {{yes}}

| {{yes}} CYREN

| {{yes}} CYREN

{{rh}}| Citadel

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{optional}} (via SpamAssassin)

| {{dunno}}

| {{dunno}}

| {{no}}

| {{optional}} (via SpamAssassin)

| {{no}}

| {{optional}} (ClamAV)

| {{optional}} (SpamAssassin)

{{rh}}| Courier Mail Server

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}{{cite web|url=http://phantom.dragonsdawn.net/~gordon/courier-pythonfilter/|title=Index of /~gordon/courier-pythonfilter|website=phantom.dragonsdawn.net}}

| {{yes}}

| {{optional}}Two DKIM filters can be found in Courier-MTA's [http://www.courier-mta.org/links.html links] page

| {{optional}}With {{cite web |url=http://www.tana.it/sw/zdkimfilter/#dmarc |title=zdkimfilter}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}} Clamav

| {{yes}}

{{rh}}| Dovecot

| {{No}}Considered and rejected by developers in 2013. {{Cite web|last=Fawcett|first=John|date=2013-07-03|title=[Dovecot] dnsbl feature for dovecot|url=https://dovecot.org/list/dovecot/2013-July/091236.html|url-status=live|archive-url=https://web.archive.org/web/20220225204208if_/https://dovecot.org/list/dovecot/2013-July/091236.html|archive-date=2022-02-25|access-date=2022-02-25|website=dovecot.org|language=en|df=mdy-all}}

| {{No}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| Eudora Internet Mail Server

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| Exim

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{optional}} (at build time, most distributions do)

| {{optional}} (at build time, most distributions do)

| {{optional}} (at build time, most distributions do)

| {{yes}}

| {{optional}} with spamassassin etc.

| {{yes}}

| {{optional}} any

| {{optional}} any

{{rh}}| FirstClass

| {{yes}}

| {{yes}}

| {{no}}

| {{dunno}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}} Symantec

| {{dunno}}

{{rh}}| Gordano Messaging Suite

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}} CYREN, Authentium

| {{yes}} CYREN

{{rh}}| GroupWise

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| Halon

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{optional}} (via SpamAssassin)

| {{yes}}

| {{optional}} (Sophos, ClamAV)

| {{optional}} (CYREN, SpamAssassin, Eleven eXpurgate{{cite web|url=https://docs.halon.io/expurgate/|title=eXpurgate anti-spam — eXpurgate Anti-Spam documentation|date=28 March 2025|website=docs.halon.io}})

{{rh}}| Haraka

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{optional}} with spamassassin etc.

| {{yes}}

| {{optional}} ClamAV, AVG, any via plugins

| {{optional}} SpamAssassin, MessageSniffer

{{rh}}|HCL Domino

| {{yes}}{{cite web|url=https://help.hcl-software.com/domino/14.0.0/admin/conf_restrictingsmtpinboundrouting_c.html|title=HCL Domino Documentation - Restricting SMTP inbound routing|date=30 June 2024|website=help.hcl-software.com}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{yes}}{{cite web|url=https://help.hcl-software.com/domino/14.0.0/admin/conf_configure_domino_smtp_server_to_reduce_spam.html|title=Configuring the Domino SMTP server to reduce spam|date=5 June 2024|website=help.hcl-software.com}}

| {{yes}}{{cite web|url=https://help.hcl-software.com/domino/14.0.0/admin/conf_dkimsigning.html|title=Configuring DKIM signing for messages routed to external Internet domains|date=5 June 2024|website=help.hcl-software.com}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{optional}} with ICAP

| {{dunno}}

{{rh}}| hMailServer

| {{yes}}

| {{yes}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}} ClamAV

| {{yes}} SpamAssassin

{{rh}}| IceWarp Mail Server

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

{{rh}}| Ipswitch IMail Server

| {{yes}}

| {{yes}}

| {{no}}

| {{no}}

| {{yes}}

| {{yes}}{{cite web|url=http://www.imailserver.com/products/imail-secure-server/|title=IMail Secure Mail Server - Ipswitch|first=Ipswitch|last=Inc.|website=www.imailserver.com}}

| {{yes}}{{cite web|url=http://www.imailserver.com/support/patches-upgrades/imail-server-v12-5-2/|title=Your IMail Software Upgrades and Patches - Ipswitch IMail Server|first=Ipswitch|last=Inc.|website=www.imailserver.com}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}} Symantec, BitDefender

| {{yes}} CYREN

{{rh}}| Kolab

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{optional}} with spamassassin etc.

| {{yes}}

| {{optional}} (via [http://www.postfix.org/FILTER_README.html content filter] interface)

| {{optional}} (via [http://www.postfix.org/FILTER_README.html content filter] interface)

{{rh}}| Mailsite

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{no}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

{{rh}}| Mailtraq

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| MDaemon

| {{yes}}

| {{yes}} (via SpamAssassin)

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}} (via SpamAssassin)

| {{yes}} (via Content Filter)

| {{optional}} Cyren, ClamAV

| {{yes}} SpamAssassin

{{rh}}| Mercury Mail Transport System

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}} (GreyWall extension)

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{yes}} (SpamHalter extension)

| {{dunno}}

| {{yes}} (ClamWall extension)

| {{dunno}}

{{rh}}| Microsoft Exchange Server

| {{yes}} (2003 & later)

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{optional}} (Signing only via 3rd Party Extensions)

| {{dunno}}

| {{yes}} (2003 & later)

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| NetMail

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| OpenSMTPD

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{optional}}With {{cite web |url=https://imperialat.at/dev/filter-dkimsign/ |title=filter-dkimsign}} or {{cite web |url=https://github.com/poolporg/filter-rspamd |title=filter-rspamd|website=GitHub |date=15 October 2022 }}

| {{optional}}With {{cite web |url=https://github.com/poolporg/filter-rspamd |title=filter-rspamd|website=GitHub |date=15 October 2022 }}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| Oracle Communications Messaging Server

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}}

| {{dunno}}

| {{dunno}}

| {{yes}}

| {{optional}} with spamassassin etc.

| {{yes}}

| {{optional}} any

| {{optional}} any

{{rh}}| Postfix

| {{yes}}

| {{yes}} (via milter-link)

| {{dunno}}

| {{yes}}

| {{yes}}

| {{optional}}{{cite web|url=http://www.opendkim.org/|title=OpenDKIM|website=www.opendkim.org}}

| {{optional}}{{cite web|url=http://www.trusteddomain.org/opendmarc.html|title=Trusted Domain Project - About Us|website=www.trusteddomain.org}}

| {{yes}}

| {{optional}} with spamassassin etc.

| {{yes}}

| {{optional}} (via [http://www.postfix.org/FILTER_README.html content filter] interface)

| {{optional}} (via [http://www.postfix.org/FILTER_README.html content filter] interface)

{{rh}}| qmail

| {{yes}}

| with patch

| {{dunno}}

| {{yes}}

| with patch, {{nowrap|s/qmail}}

| with patch, {{nowrap|s/qmail}}

| {{dunno}}

| with patch, {{nowrap|s/qmail}}

| {{no}}

| {{dunno}}

| {{no}}

| {{no}}

{{rh}}| Scalix

| {{yes}}

| {{yes}} (via Scalix AntiSpam powered by Cyren or SpamAssassin)

| {{yes}} (via Scalix AntiSpam powered by Cyren or SpamAssassin)

| {{yes}}

| {{yes}} (via Scalix AntiSpam powered by Cyren or SpamAssassin)

| {{yes}} (via Scalix AntiSpam powered by Cyren or SpamAssassin)

| {{yes}} (via Scalix AntiSpam powered by Cyren or SpamAssassin)

| {{yes}}

| {{yes}}

| {{yes}}

| {{yes}} (via Scalix ZeroHour AntiVirus powered by Cyren or ClamAV)

| {{yes}}

{{rh}}| Sendmail

| {{yes}}

| {{yes}} (via milter/SA)

| {{dunno}}

| {{yes}}

| {{optional}}

| {{optional}}

| {{optional}}

| {{dunno}}

| {{optional}} with spamassassin etc.

| {{yes}}

| {{yes}} ClamAV

| {{yes}} SpamAssassin

{{rh}}| SparkEngine

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| UW IMAP

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}|WinGate

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

| {{dunno}}

{{rh}}| Zarafa

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

| {{optional|External}}

{{rh}}| Zimbra

| {{yes}}

| {{yes}} (via SpamAssassin)

| {{dunno}}

| {{yes}} (via Cluebringer Policy Daemon)

| {{yes}}

| {{yes}}

| {{dunno}}

| {{yes}}

| {{yes}}

| {{yes}} (partially)

| {{yes}} (via ClamAV, optionally any via Amavisd)

| {{yes}} (via SpamAssassin)

class="sortbottom"

! Mail Server

! DNSBL

! SURBL

! Spamtraps

! Greylisting

! SPF

! DKIM

! DMARC

! Tarpit

! Bayesian filters

! Regular expressions

! Embedded Antivirus

! Embedded Antispam

See also

References

{{Reflist|30em}}

Category:Message transfer agents

Mail servers