Syntax: protocol imap | pop3 | smtp; Default: — Context: server Sets the protocol for a proxied server. Supported protocols are IMAP, POP3, and SMTP. If the directive is not set, the protocol can be detected automatically based on the well-known port specified in the listen directive: imap: 143, 993 pop3: 110, 995 smtp: 25, 587, 465 Unnecessary protocols can be disabled using the configuration parameters --without-mail_imap_module, --without-mail_pop3_module, and

Syntax: preread_timeout timeout; Default: preread_timeout 30s; Context: stream, server This directive appeared in version 1.11.5. Specifies a timeout of the preread phase.

Syntax: preread_buffer_size size; Default: preread_buffer_size 16k; Context: stream, server This directive appeared in version 1.11.5. Specifies a size of the preread buffer.

Syntax: postpone_output size; Default: postpone_output 1460; Context: http, server, location If possible, the transmission of client data will be postponed until nginx has at least size bytes of data to send. The zero value disables postponing data transmission.

Syntax: port_in_redirect on | off; Default: port_in_redirect on; Context: http, server, location Enables or disables specifying the port in absolute redirects issued by nginx. The use of the primary server name in redirects is controlled by the server_name_in_redirect directive.

Syntax: pop3_capabilities extension ...; Default: pop3_capabilities TOP USER UIDL; Context: mail, server Sets the POP3 protocol extensions list that is passed to the client in response to the CAPA command. The authentication methods specified in the pop3_auth and (SASL extension) and STLS directives, are automatically added to this list if the starttls directive is enabled. It makes sense to specify the extensions supported by the POP3 backends to which the clients are proxied (i

Syntax: pop3_auth method ...; Default: pop3_auth plain; Context: mail, server Sets permitted methods of authentication for POP3 clients. Supported methods are: plain USER/PASS, AUTH PLAIN, AUTH LOGIN. It is not possible to disable these methods. apop APOP. In order for this method to work, the password must be stored unencrypted. cram-md5 AUTH CRAM-MD5. In order for this method to work, the password must be stored unencrypted. external AUTH EXTERNAL (1.11.6).

Syntax: pid file; Default: pid nginx.pid; Context: main Defines a file that will store the process ID of the main process.

Syntax: perl_set $variable module::function|'sub { ... }'; Default: — Context: http Installs a Perl handler for the specified variable.

Syntax: perl_require module; Default: — Context: http Defines the name of a module that will be loaded during each reconfiguration. Several perl_require directives can be present.