Linux系统非ROOT用户80端口不能启动tomcat问题的变通办法――通过Iptables端口转发

非root用户，修改tomcat启动端口为80，启动时报错：

2010-07-17 13:21:42 org.apache.tomcat.util.digester.SetPropertiesRule begin
警告: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'debug' to '0' did not find a matching property.
2010-07-17 13:21:42  org.apache.catalina.core.AprLifecycleListener init
信 息: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /usr/jdk1.5.0_16/jre/lib/i386/client:/usr/jdk1.5.0_16/jre/lib/i386:/usr/jdk1.5.0_16/jre/../lib/i386
2010-07-17 13:21:42  org.apache.coyote.http11.Http11Protocol init
严重: Error initializing endpoint
java.net.BindException: Permission denied:80
        at org.apache.tomcat.util.net.JIoEndpoint.init(JIoEndpoint.java:502)
        at org.apache.coyote.http11.Http11Protocol.init(Http11Protocol.java:176)
        at org.apache.catalina.connector.Connector.initialize(Connector.java:1058)
        at org.apache.catalina.core.StandardService.initialize(StandardService.java:677)
        at org.apache.catalina.core.StandardServer.initialize(StandardServer.java:795)
        at org.apache.catalina.startup.Catalina.load(Catalina.java:530)
        at org.apache.catalina.startup.Catalina.load(Catalina.java:550)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:585)
        at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:260)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:412)
2010-07-17 13:21:43 org.apache.catalina.startup.Catalina load

 

上面可以看到，非root用户其实没有绑定80端口的权限。在Linux下低于1024的端口是root专用，而Tomcat安装后默认使用用户 tomcat启动的，所以将端口改为80后启动，会产生错误：java.net.BindException: Permission denied:80

解决方法是：

第一步，重将Tomcat的端口（server.xml）由80改回8080。

第二步，通过Iptables端口实现80到8080的转发，命令为：

iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080

 

用root用户直接去执行就可以了！

这样，用户访问80端口和8080端口其实都到了8080端口。