| 1 | agorum core | Yes | No | No | No | Yes | Yes | PLAIN, LOGIN, CRAM-MD5, NTLM |
| 2 | Apache James | Yes | ? | ? | ? | Yes | Yes | PLAIN, LOGIN |
| 3 | Atmail | Yes | Yes | Yes | Yes | Yes | Yes | PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, Active Directory, any LDAP-compatible source |
| 4 | Axigen | Yes | No | Yes | No | No | Yes | GSSAPI, CRAM-MD5, DIGEST-MD5, APOP, CLRTXT, LOGIN, PLAIN, LDAP, Internal |
| 5 | CommuniGate Pro | Yes | Yes | Yes | Yes | Yes | Yes | 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 |
| 6 | Courier Mail Server | Yes | Yes | Yes | Yes | Yes | Yes | Managed by Courier authentication library which can use PAM, Userdb, PostgreSQL(beta), MySQL, LDAP, and EXTERNAL. |
| 7 | Cyrus IMAP | No | Yes | Yes | Yes | Yes | Yes | 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, EXTERNAL, GSSAPI, LOGIN, NTLM, OTP, PASSDSS, PLAIN, SRP |
| 8 | Dovecot | No | Yes | Yes | Yes | Yes | Yes | Not an SMTP server, but offers SASL to MTAs. http://wiki.dovecot.org/DovecotFeatureshttp://wiki.dovecot.org/Authentication. 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-SHA1, EXTERNAL, GSSAPI, NTLM, OTP, SKEY, RPA. |
| 9 | Eudora Internet Mail Server | Yes | No | Yes | Yes | No | No | CRAM-MD5, DIGEST-MD5, PLAIN, LOGIN |
| 10 | Exim | Yes | Yes | Yes | Yes | Yes | Yes | Cyrus SASL, Dovecot SASL, GNU SASL, CRAM-MD5, Heimdal GSSAPI, PLAIN, LOGIN, SPA |
| 11 | FirstClass | Yes | ? | ? | Yes | Yes | Yes | |
| 12 | Gordano Messaging Suite | Yes | Yes | Yes | No | Yes | Yes | PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, APOP, ODBC, Active Directory, NT Domain |
| 13 | GroupWise | Yes | Yes | Yes | Yes | Yes | Yes | eDirectory, Any LDAPv3-compliant source |
| 14 | Haraka | Yes | No | No | Yes | Yes | Yes | Proxy to other server, any other mechanism via AUTH plugins. |
| 15 | IceWarp Mail Server | Yes | Yes | Yes | Yes | Yes | Yes | PLAIN, LOGIN, CRAM-MD5, NTLM |
| 16 | Ipswitch IMail Server | Yes | No | Yes | Yes | Yes | Yes | Active Directory, Windows authentication, CRAM-MD5, PLAIN, LOGIN |
| 17 | Kolab | Yes | Yes | Yes | Yes | Yes | Yes | Kolab employs Cyrus and Postfix and thus supports all Cyrus SASL authentication methods and X.509 PKI auth viaSTARTTLS and EXTERNAL. |
| 18 | Kerio Connect | Yes | Yes | Yes | Yes | Yes | Yes | Active Directory, Apple Open Directory, Pluggable Authentication Modules, PLAIN, LOGIN, CRAM-MD5, internal user database |
| 19 | MagicMail | Yes | No | No | Yes | Yes | No | ? |
| 20 | Mailsite | Yes | No | Yes | Yes | Yes | Yes | NT Domain, Active Directory, PLAIN, LOGIN, NTLM, SCRAM-MD5, CRAM-MD5 |
| 21 | Mailtraq | Yes | Yes | Yes | Yes | Yes | Yes | NT Domain, Active Directory, Local Directory |
| 22 | MDaemon Mail Server | Yes | Yes | Yes | No | Yes | Yes | Active Directory, PLAIN, CRAM-MD5, LOGIN |
| 23 | Mercury Mail Transport System | Yes | Yes | Yes | Yes | No | ? | Internal, LOGIN, PLAIN, CRAM-MD5, Netware, LDAP?, partial NT Domain |
| 24 | Microsoft Exchange Server | Yes | ? | Yes | No | No | Yes | Active Directory, LOGIN, NTLM |
| 25 | Momentum | Yes | No | No | Yes | Yes | Yes | PLAIN, LOGIN, CRAM-MD5, LDAP |
| 26 | NetMail | Yes | Yes | Yes | Yes | Yes | Yes | eDirectory, LDAP |
| 27 | Oracle Communications Messaging Server | Yes | Yes | Yes | Yes | Yes | Yes | Plain, Login, CRAM-MD5, Digest-MD5, Certificate |
| 28 | OpenSMTPD | Yes | No | No | Yes | Yes | Yes | By default PLAIN and LOGIN over SSL only, Certificates, bsd_auth and PAM. Supports adding new authentication mechanisms through custom backends. |
| 29 | Postfix | Yes | No | No | Yes | Yes | Yes | Supports all Cyrus SASL authentication methods except for APOP. |
| 30 | Qpopper | No | Yes | Yes | Yes | Yes | Yes | Pluggable Authentication Modules,GSSAPI, CRAM-MD5, DIGEST-MD5, APOP, PLAIN, LDAP, CMU SASL library, Kerberos |