Tomcat configuration HTTPS error Java net. SocketException: Permission denied

1. Error message

Today, when configuring HTTPS certificate for tomcat, an error was reported when starting Tomcat:

25-Jan-2022 22:01:59.398 SEVERE [main] org.apache.catalina.core.StandardService.initInternal Failed to initialize connector [Connector[HTTP/1.1-443]]
        org.apache.catalina.LifecycleException: Protocol handler initialization failed
                at org.apache.catalina.connector.Connector.initInternal(Connector.java:1060)
                at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:136)
                at org.apache.catalina.core.StandardService.initInternal(StandardService.java:552)
                at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:136)
                at org.apache.catalina.core.StandardServer.initInternal(StandardServer.java:848)
                at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:136)
                at org.apache.catalina.startup.Catalina.load(Catalina.java:639)
                at org.apache.catalina.startup.Catalina.load(Catalina.java:662)
                at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
                at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.lang.reflect.Method.invoke(Method.java:498)
                at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:303)
                at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:473)
        Caused by: java.net.SocketException: Permission denied
                at sun.nio.ch.Net.bind0(Native Method)
                at sun.nio.ch.Net.bind(Net.java:438)
                at sun.nio.ch.Net.bind(Net.java:430)
                at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:225)
                at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
                at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:221)
                at org.apache.tomcat.util.net.AbstractEndpoint.init(AbstractEndpoint.java:1118)
                at org.apache.tomcat.util.net.AbstractJsseEndpoint.init(AbstractJsseEndpoint.java:223)
                at org.apache.coyote.AbstractProtocol.init(AbstractProtocol.java:587)
                at org.apache.coyote.http11.AbstractHttp11Protocol.init(AbstractHttp11Protocol.java:74)
                at org.apache.catalina.connector.Connector.initInternal(Connector.java:1058)
                ... 13 more

The reason for the error is: java.net.Socketexception: permission denied , which is obviously a network permission problem. The reason for this problem is that the Linux operating system does not allow non root users to use ports less than 1024.

2. Solutions

1. Use the root account to start Tomcat
2. Change the port number to a port number greater than 1024, but add the port number to the URL request
3. Change the port number to a port number greater than 1024, and use iptables to forward port 443 to the configured port. The command is as follows:

#Execute the commands under the root
# Mapping port 443 to 8443
iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-port 8443