센드메일에서 메일을 보내면 다른 곳은 수신이 되는데
한메일에선 메일이 바로 리턴되어 돌아옵니다.
 리턴된 메일의 에러 메시지는 아래와 같습니다.
이런 현상이 발생하는 원인과 해결책을 아시는 분은
답변을 꼭 올려주시면 감사하겠습니다.
 와우리눅스 7.0 입니다.
 The original message was received at Thu, 25 Apr 2002 15:47:48 +0900
from localhost.localdomain [127.0.0.1]
    ----- The following addresses had permanent fatal errors -----
test at hanmail.net     (reason: 501 5.0.0 HELO requires domain address)
    ----- Transcript of session follows -----
... while talking to mx1.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx4.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx7.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx8.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx6.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx9.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx5.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx10.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx2.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
... while talking to mx3.hanmail.net.:
>>> HELO
<<< 501 5.0.0 HELO requires domain address
554 5.0.0 test at hanmail.net... Service unavailable