libesmtp: libesmtp (Mail Transport Agent Library) libesmtp: libesmtp: libESMTP is an SMTP client which manages posting (or submission of) libesmtp: electronic mail via a preconfigured Mail Transport Agent (MTA). libesmtp: libESMTP supports many SMTP extensions, notably PIPELINING (RFC 2920), libesmtp: DSN (RFC 1891) and SASL authentication (RFC 2554). SMTP AUTH is libesmtp: implemented using a SASL client library integrated into libESMTP. libesmtp: libesmtp: libesmtp: libesmtp: