NSS (nss)

Deprecated: 2.3.0

NOTE

This userdb is probably useless with Dovecot Core v2.0.12+, since it uses getpwnam_r(), which supports error reporting.

Usually NSS is used with passwd authentication database but it has one problem: it can't distinguish between temporary and permanent errors.

So if you're using, e.g., nss_ldap and your LDAP database is down, all userdb lookups may return "user doesn't exist" errors. This is especially bad if you're using LDA, which causes the mails to be bounced back to sender.

The NSS userdb works around this problem by loading the NSS modules and calling them itself. This is a bit kludgy, and it probably works only with Linux.

Database Parameters

service=<name>

The name specifies what NSS module to use, for example ldap.

This parameter is REQUIRED.

blocking=no

Causes the lookups to be done in auth master processes instead of in worker processes.

Example

userdb {
  driver = nss
  args = service=ldap
}