--name

Specifies the handler name. The string is allowed to contain any character allowed in UNIX file name (that is, anything except slash and NUL). Registration will fail if a handler with the specified name has already been registered.

--type

Specifies the type of a handler, may take the following values:

• global
  handler is called for all messages.
• sender-domain
  handler is called for messages whenever the domain part of the sender address matches the specified domain
• recipient-domain
  handler is called for messages whenever the domain part of one of the recipient addresses matches the specified domain
• sender
  handler is called for messages whenever the sender address matches the specified address
• recipient
  handler is called for messages whenever any of the recipient addresses matches the specified address

--mailname

Specifies a domain or a mail address for the handler-type.

Not required if the handler type is global.

--priority

Specifies the hook priority in the queue of hooks.

--executable

Specifies the handler executable file.

Registration will fail if the file does not exist.

--context

Specifies the context. This is an opaque string to be passed to the handler on the command line.

--enabled

Specifies whether to enable the handler.

--queue

Specifies the hooking point. Should be one of: before-queue, before-local, before-remote, before-data.

See Hooking Points for details.