SSPI is a Windows
technology for secure authentication with single sign-on.
PostgreSQL will use SSPI in
negotiate mode, which will use
Kerberos when possible and automatically
fall back to NTLM in other cases.
SSPI and GSSAPI
interoperate as clients and servers, e.g., an
SSPI client can authenticate to an
GSSAPI server. It is recommended to use
SSPI on Windows clients and servers and
GSSAPI on non-Windows platforms.
When using Kerberos authentication, SSPI works the same way GSSAPI does; see Section 20.6 for details.
The following configuration options are supported for SSPI:
include_realm
If set to 0, the realm name from the authenticated user principal is
stripped off before being passed through the user name mapping
(Section 20.2). This is discouraged and is
primarily available for backwards compatibility, as it is not secure
in multi-realm environments unless krb_realm is
also used. It is recommended to
leave include_realm set to the default (1) and to
provide an explicit mapping in pg_ident.conf to convert
principal names to PostgreSQL user names.
compat_realm
If set to 1, the domain's SAM-compatible name (also known as the
NetBIOS name) is used for the include_realm
option. This is the default. If set to 0, the true realm name from
the Kerberos user principal name is used.
Do not disable this option unless your server runs under a domain account (this includes virtual service accounts on a domain member system) and all clients authenticating through SSPI are also using domain accounts, or authentication will fail.
upn_username
If this option is enabled along with compat_realm,
the user name from the Kerberos UPN is used for authentication. If
it is disabled (the default), the SAM-compatible user name is used.
By default, these two names are identical for new user accounts.
Note that libpq uses the SAM-compatible name if no explicit user name is specified. If you use libpq or a driver based on it, you should leave this option disabled or explicitly specify user name in the connection string.
map
Allows for mapping between system and database user names. See
Section 20.2 for details. For an SSPI/Kerberos
principal, such as username@EXAMPLE.COM (or, less
commonly, username/hostbased@EXAMPLE.COM), the
user name used for mapping is
username@EXAMPLE.COM (or
username/hostbased@EXAMPLE.COM, respectively),
unless include_realm has been set to 0, in which case
username (or username/hostbased)
is what is seen as the system user name when mapping.
krb_realmSets the realm to match user principal names against. If this parameter is set, only users of that realm will be accepted. If it is not set, users of any realm can connect, subject to whatever user name mapping is done.