`banner`: `<string>` ('default =' `ESMTP Proxmox`)::

ESMTP banner.

`conn_count_limit`: `<integer> (0 - N)` ('default =' `50`)::

How many simultaneous connections any client is allowed to make to this service. To disable this feature, specify a limit of 0.

`conn_rate_limit`: `<integer> (0 - N)` ('default =' `0`)::

The maximal number of connection attempts any client is allowed to make to this service per minute. To disable this feature, specify a limit of 0.

`dnsbl_sites`: `<string>` ::

Optional list of DNS white/blacklist domains (see postscreen_dnsbl_sites parameter).

`dnsbl_threshold`: `<integer> (0 - N)` ('default =' `1`)::

The inclusive lower bound for blocking a remote SMTP client, based on its combined DNSBL score (see postscreen_dnsbl_threshold parameter).

`dwarning`: `<integer> (0 - N)` ('default =' `4`)::

SMTP delay warning time (in hours).

`greylist`: `<boolean>` ('default =' `1`)::

Use Greylisting.

`helotests`: `<boolean>` ('default =' `0`)::

Use SMTP HELO tests.

`hide_received`: `<boolean>` ('default =' `0`)::

Hide received header in outgoing mails.

`maxsize`: `<integer> (1024 - N)` ('default =' `10485760`)::

Maximum email size. Larger mails are rejected.

`message_rate_limit`: `<integer> (0 - N)` ('default =' `0`)::

The maximal number of message delivery requests that any client is allowed to make to this service per minute.To disable this feature, specify a limit of 0.

`rejectunknown`: `<boolean>` ('default =' `0`)::

Reject unknown clients.

`rejectunknownsender`: `<boolean>` ('default =' `0`)::

Reject unknown senders.

`spf`: `<boolean>` ('default =' `1`)::

Use Sender Policy Framework.

`verifyreceivers`: `<450 | 550>` ::

Enable receiver verification. The value spefifies the numerical reply code when the Postfix SMTP server rejects a recipient address.