Sets the size of the buffer used for proxying. By default, the buffer size is equal to one memory page. Depending on a platform, it is either 4K or 8K.
Indicates whether to pass the error message obtained during the authentication on the backend to the client.
Usually, if the authentication in nginx is a success, the backend cannot return an error. If it nevertheless returns an error, it means some internal error has occurred. In such case the backend message can contain information that should not be shown to the client. However, responding with an error for the correct password is a normal behavior for some POP3 servers. For example, CommuniGatePro informs a user about mailbox overflow or other events by periodically outputting the authentication error. The directive should be enabled in this case.
timeout between two successive
read or write operations on client or proxied server connections.
If no data is transmitted within this time, the connection is closed.
Enables or disables the passing of the XCLIENT command with client parameters when connecting to the SMTP backend.
XCLIENT, the MTA is able to write client information
to the log and apply various limitations based on this data.
XCLIENT is enabled
then nginx passes the following commands when connecting to the backend:
EHLOwith the server name
HELO, as passed by the client
If the name
by the client IP address points to the same address,
it is passed in the
If the name could not be found, points to a different address,
or resolver is not specified,
[UNAVAILABLE] is passed
If an error has occurred in the process of resolving,
[TEMPUNAVAIL] value is used.
XCLIENT is disabled
then nginx passes the
EHLO command with the
when connecting to the backend if the client has passed
HELO with the server name, otherwise.