Interfacing Protocols
Amavis can receive mail messages from an MTA over one or more sockets of protocol families PF_INET (IPv4), PF_INET6 (IPv6) or PF_LOCAL (Unix domain socket), using protocols ESMTP, LMTP, or a simple private protocol AM.PDP can be used with a helper program like amavisd-milter to interface with milters. On the output side protocols ESMTP or LMTP can be used to pass a message to a back-end MTA instance or to an LDA, or a message can be passed to a spawned process over a Unix pipe. When ESMTP or LMTP are used, a session can optionally be encrypted using a TLS STARTTLS (RFC 3207) extension to the protocol. SMTP Command Pipelining (RFC 2920) is supported in client and server code.
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