Using telnet to send test emails over smtp fails when using stdin-redirection (pipes or heredocs)

Issue

• I'm using a script that tests smtp email connectivity. The script uses the telnet command and worked in HP-UX but I can't get it to work in RHEL ... it always fails.

  telnet mailserver 25 <<EOF
  HELO        xxxx
  MAIL FROM:  xxxx
  RCPT TO:    xxxx
  SUBJECT:    xxxx
  DATA
  From:       xxxx
  To:         xxxx
  Subject:    xxxx
  xxxxx (body here) xxxx
  .
  QUIT
  EOF