Chapter 2[ 37 ]NGINX can proxy the IMAP, POP3, and SMTP protocols. The following table lists
the directives that are available to this module:
Table: Mail module directives
Directive Explanation
auth_http Specifies the server used for authenticating
the POP3/IMAP user. The functionality
of this server will be discussed in detail
in Chapter 3.
imap_capabilities Indicates which IMAP4 capabilities are
supported by the backend server.
pop3_capabilities Indicates which POP3 capabilities are
supported by the backend server.
protocol Indicates which protocol is supported by
this virtual server context.
proxy This directive will simply enable or disable
mail proxying.
proxy_buffer This directive allows setting the size of the
buffer used for the proxy connection beyond
the default of one page.
proxy_pass_error_message Useful in situations where the backend
authentication process emits a useful error
message to the client.
proxy_timeout If a timeout beyond the default of 24 hours
is required, this directive can be used.
xclient The SMTP protocol allows checking based
on IP/HELO/LOGIN parameters, which are
passed via the XCLIENT command. This
directive enables NGINX to communicate
this information.If NGINX was compiled with SSL support (--with-mail_ssl_module), the following
directives will be available in addition to the previous ones:
Table: Mail SSL directives
Directive Explanation
ssl Indicates if this context should support SSL
transactions.
ssl_certificate It specifies the path to the PEM-encoded SSL
certificate(s) for this virtual server.