二、我telnet的时候出现:
[root@email]# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
Connection closed by foreign host.
[root@email]# telnet localhost 110
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
+OK <12280.1141982053@email>
user test
+OK
pass test
-ERR unable to write pipe
Connection closed by foreign host.