$ lsnrctl start

LSNRCTL for Linux: Version 11.1.0.6.0 - Production on 20-JUL-2009 13:32:08

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Starting /u01/app/oracle/product/11.1.0/db_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.1.0.6.0 - Production
System parameter file is /u01/app/oracle/product/11.1.0/db_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/diag/tnslsnr/liang/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=hostname)(PORT=1521)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=PNPKEY)))

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=hostname)(PORT=1521))
TNS-12547: TNS:lost contact
 TNS-12560: TNS:protocol adapter error
  TNS-00517: Lost contact
   Linux Error: 104: Connection reset by peer
Connecting to (ADDRESS=(PROTOCOL=ipc)(KEY=PNPKEY))
TNS-12541: TNS:no listener
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   Linux Error: 111: Connection refused


导致这种原因一般有两种：
一、由于listener的日志太大，超过2G就会报这错。
二、由于/etc/hosts里没有设置回环网络loopback，添加以下行到/etc/hosts
        127.0.0.1 localhost