아래와 같이 에러 메세지가 나옵니다. 또한 root로 해도 마찬가지 입니다. [min@toms min]$ telnet localhost 25 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 toms.sk ESMTP Sendmail 8.11.6/8.11.6; Sat, 29 Dec 2001 12:12:15 +0900 quit 221 2.0.0 toms.sk closing connection Connection closed by foreign host. [min@toms min]$ telnet 192.168.121.42 25 Trying 192.168.121.42... telnet: connect to address 192.168.121.42: Connection refused [min@toms min]$