사용버전 : sendmail-8.12.1-2kr
 # host mail.roco.dnip.net       
mail.roco.dnip.net. has address 211.57.203.111
DNS 설정
         IN      NS      ns.roco.dnip.net.
        IN      A       211.57.203.111
        IN      MX 10   mail.roco.dnip.net.
mail    IN      A       211.57.203.111
 # cat /etc/mail/local-host-name
roco.dnip.net
mail.roco.dnip.net
 # cat /etc/mail/sendmail.cf |grep Cw
Cwlocalhost
 or
(이것도 해봤지만..)
Cwlocalhost roco.dnip.net mail.roco.dnip.net
 # cat /etc/mail/sendmail.cf |grep Fw
Fw/etc/mail/local-host-names
  다움에서 보냈는데 다음과 같이 반송되어 버렸습니다.
뭐가 문제인지 모르겠네요. 받는거는 local-host-name 만 설정되면
되는것 같던데.. 자꾸 반송해버리네요..
 The original message was received at Mon, 19 Nov 2001 09:01:09 +0900
from www12.hanmail.net [211.32.117.32]
 ----- The following addresses had permanent fatal errors -----
<roco at roco.dnip.net>
(reason: 550 5.7.1 <roco at roco.dnip.net>... Relaying denied)
 ----- Transcript of session follows -----
... while talking to mail.roco.dnip.net.:
>>> RCPT To:<roco at roco.dnip.net>
<<< 550 5.7.1 <roco at roco.dnip.net>... Relaying denied
550 5.1.1 <roco at roco.dnip.net>... User unknown
  Reporting-MTA: dns; smail-101.hanmail.net
Arrival-Date: Mon, 19 Nov 2001 09:01:09 +0900
 Final-Recipient: RFC822; roco at roco.dnip.net Action: failed
Status: 5.7.1
Remote-MTA: DNS; mail.roco.dnip.net
Diagnostic-Code: SMTP; 550 5.7.1 <roco at roco.dnip.net>... Relaying denied
Last-Attempt-Date: Mon, 19 Nov 2001 09:03:06 +0900