tomcat报Network is unreachable

今天在虚拟机中新装了个RedHat5.5版的，装好JDK和tomcat，但是在运行tomcat的时候却报了：

SEVERE: Protocol handler pause failed
java.net.SocketException: Network is unreachable
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
        at java.net.Socket.connect(Socket.java:529)
        at java.net.Socket.connect(Socket.java:478)
        at java.net.Socket.<init>(Socket.java:375)
        at java.net.Socket.<init>(Socket.java:218)
        at org.apache.jk.common.ChannelSocket.unLockSocket(ChannelSocket.java:486)
        at org.apache.jk.common.ChannelSocket.pause(ChannelSocket.java:283)
        at org.apache.jk.server.JkMain.pause(JkMain.java:681)
        at org.apache.jk.server.JkCoyoteHandler.pause(JkCoyoteHandler.java:153)
        at org.apache.catalina.connector.Connector.pause(Connector.java:1073)
        at org.apache.catalina.core.StandardService.stop(StandardService.java:563)
        at org.apache.catalina.core.StandardServer.stop(StandardServer.java:744)
        at org.apache.catalina.startup.Catalina.stop(Catalina.java:628)
        at org.apache.catalina.startup.Catalina$CatalinaShutdownHook.run(Catalina.java:671)
Sep 18, 2011 2:37:56 AM org.apache.catalina.core.StandardService stop

 由于是linux新手，开始没有查出是什么原因，以为是tomcat没有配置好；但是看到java.net.SocketException: Network is unreachable才知道原来是防火墙没有关，随后关掉防火墙之后，在windows下通过http://192.168.56.128:8080/访问linux中的tomcat正常。

下面贴出linux下关闭防火墙的命令：

1) 重启后生效

开启： chkconfig iptables on

关闭： chkconfig iptables off
2) 即时生效，重启后失效
开启： service iptables start
关闭： service iptables stop