Comparison of mail servers on arvau

Wikipedia / Comparison of mail servers

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 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.

Mail server	Other
agorum core	PLAIN, LOGIN, CRAM-MD5, NTLM
Apache James	PLAIN, LOGIN
Axigen	GSSAPI, CRAM-MD5, DIGEST-MD5, APOP, CLRTXT, LOGIN, PLAIN, LDAP, Internal
CommuniGate Pro	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
Courier Mail Server	Managed by Courier authentication library which can use PAM, Userdb, PostgreSQL(beta), MySQL, LDAP, and EXTERNAL.
Cyrus IMAP	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
DBMail	LOGIN, Active Directory, OpenLDAP
Dovecot	Submission service supports SMTP AUTH. Offers SASL to MTAs. 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.
Eudora Internet Mail Server	CRAM-MD5, DIGEST-MD5, PLAIN, LOGIN
Exim	Cyrus SASL, Dovecot SASL, GNU SASL, CRAM-MD5, Heimdal GSSAPI, PLAIN, LOGIN, SPA
FirstClass
Gordano Messaging Suite	PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, APOP, ODBC, Active Directory, NT Domain
GroupWise	eDirectory, Any LDAPv3-compliant source
Halon	Many mechanism (SMTP callout, Dovecot SASL, REST, etc.) via script.
Haraka	Proxy to other server, any other mechanism via AUTH plugins.
HCL Domino	Passkeys, Time-based one-time password
IceWarp Mail Server	PLAIN, LOGIN, CRAM-MD5, NTLM
Ipswitch IMail Server	Active Directory, Windows authentication, CRAM-MD5, PLAIN, LOGIN
Kolab	Kolab employs Cyrus and Postfix and thus supports all Cyrus SASL authentication methods and X.509 PKI auth via STARTTLS and EXTERNAL.
maddy	PLAIN, LOGIN
Mailsite	NT Domain, Active Directory, PLAIN, LOGIN, NTLM, SCRAM-MD5, CRAM-MD5
Mailtraq	NT Domain, Active Directory, Local Directory
MDaemon
Mercury Mail Transport System	Internal, LOGIN, PLAIN, CRAM-MD5, Netware, LDAP?, partial NT Domain
Microsoft Exchange Server	Active Directory, LOGIN, NTLM
mox	PLAIN, LOGIN, CRAM-MD5, SCRAM-SHA-1, SCRAM-SHA-256 (both with channel binding variants), EXTERNAL
NetMail	eDirectory, LDAP
Oracle Communications Messaging Server	Plain, Login, CRAM-MD5, DIGEST-MD5, Certificate
OpenSMTPD	By default PLAIN and LOGIN over SSL only, Certificates, bsd_auth and PAM. Supports adding new authentication mechanisms through custom backends.
Postfix	Supports all Cyrus SASL authentication methods except for APOP.
Qpopper	Pluggable Authentication Modules, GSSAPI, CRAM-MD5, DIGEST-MD5, APOP, PLAIN, LDAP, CMU SASL library, Kerberos
qmail	Works with any checkpassword utility. The original supports only LOGIN and PLAIN. Alternate checkpassword utilities support authentication against PAM, LDAP, and databases.
Scalix	Internal, LOGIN, PLAIN, X.500 (DAP), LDAP, OpenLDAP, Active Directory, eDirectory, Kerberos, etc.
Sendmail	Supports all Cyrus SASL authentication methods except for APOP. Also supports X.509 PKI auth via STARTTLS and EXTERNAL.
Stalwart	PLAIN, LOGIN, OAUTHBEARER, XOAUTH2; also OAuth 2.0, OpenID Connect and TOTP two-factor authentication
WinGate	NT Domain, Active Directory, CRAM-MD5, SASL PLAIN, SASL LOGIN
Zarafa	PLAIN, LOGIN using internal backends: Internal, Active Directory, any LDAP-compatible source, Unix
Zentyal	Active Directory using Dovecot SASL mechanisms
Zimbra	Internal, LDAP, Open LDAP, Active Directory
Mail server	Other Authentication possibilites

Feature comparison

Authentication

Antispam features

See also

References