Here is my connector element for https <Connector SSLEnabled="true" acceptCount="100" connectionTimeout="20000" executor="tomcatThreadPool" keystoreFile="D:/.keystore" keystorePass="changeit" maxKeepAliveRequests="15" port="8443" protocol="HTTP/1.1" redirectPort="8443" scheme="https" secure="true" allowUnsafeLegacyRenegotiation="true"/>
But get below error while server start up May 06, 2014 11:09:34 AM org.apache.coyote.http11.Http11AprProtocol init SEVERE: Error initializing endpoint java.lang.Exception: No Certificate file specified or invalid file format at org.apache.tomcat.jni.SSLContext.setCertificate(Native Method) at org.apache.tomcat.util.net.AprEndpoint.init(AprEndpoint.java:832) at org.apache.coyote.http11.Http11AprProtocol.init(Http11AprProtocol.java:109) at org.apache.catalina.connector.Connector.initialize(Connector.java:1124) at org.apache.catalina.core.StandardService.initialize(StandardService.java:703) at org.apache.catalina.core.StandardServer.initialize(StandardServer.java:838) at org.apache.catalina.startup.Catalina.load(Catalina.java:538) at org.apache.catalina.startup.Catalina.load(Catalina.java:562) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:261) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413) May 06, 2014 11:09:34 AM org.apache.catalina.core.StandardService initialize SEVERE: Failed to initialize connector [Connector[HTTP/1.1-8443]] LifecycleException: Protocol handler initialization failed: java.lang.Exception: No Certificate file specified or invalid file format at org.apache.catalina.connector.Connector.initialize(Connector.java:1126) at org.apache.catalina.core.StandardService.initialize(StandardService.java:703) at org.apache.catalina.core.StandardServer.initialize(StandardServer.java:838) at org.apache.catalina.startup.Catalina.load(Catalina.java:538) at org.apache.catalina.startup.Catalina.load(Catalina.java:562) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.catalina.startup.Bootstrap.load(Bootstrap.java:261) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413) May 06, 2014 11:09:34 AM org.apache.coyote.ajp.AjpAprProtocol init INFO: Initializing Coyote AJP/1.3 on ajp-8009 May 06, 2014 11:09:34 AM org.apache.catalina.startup.Catalina load INFO: Initialization processed in 965 ms Server starts up successfully when i change the protocol to org.apache.coyote.http11.Http11Protocol . My question is why this change is required and how safe it is? I am using using tomcat 6.0.39. Any ideas ?