Memcache host MTA/channel options

Memcache MTA/channel options: (host)
The  MTA/channel option specifies the host name (or IP address) of the host providing a server supporting the memcache protocol. (The server software is often, but not always, memcached.) There is no default.

Use of  is only supported in cases where a channel-specific memcache server makes sense semantically. Currently the only channels that support this usage are those associated with the MTA-STS server.

See also:
 * Memcache MTA options