How do I disable ESMTP in xxxx mail program?
Turnpike: When sending email, Turnpike now uses the ESMTP protocol rather than SMTP. If the smarthost you are using does not support ESMTP then this will result in the initial “EHLO” command being rejected. Turnpike will then use SMTP in the usual way. Turnpike is capable of using the PIPELINING extension, which should improve the speed of handling the red tape at the start of mail sending operations.