SSL 中证书是否可以使用IP而不是域名
前言：以前听别人说生成证书时可以用IP地址，今天用例子证实了下用IP地址是不行的。
情景一：
生成证书时指定的名称为IP地址
例子是做单点登录时的例子，web.xml中配置如下：
<!--该过滤器负责用户的认证工作，必须启用它 -->
<filter>
<filter-name>CASFilter</filter-name>
<filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
<init-param>
<param-name>casServerLoginUrl</param-name>
<param-value>https://172.18.113.78:8443/CasServer/login</param-value>
<!--这里的server是服务端的IP -->
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://127.0.0.1:8080/</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CASFilter</filter-name>
<url-pattern>/*</url-pattern
</filter-mapping>
<!-- 该过滤器负责对Ticket的校验工作，必须启用它 -->
<!-- ValidationFilter 这个filter负责对请求参数ticket进行验证(ticket参数是负责子系统与CAS进行验证交互的凭证)casServerUrlPrefix:CAS服务访问地址serverName:当前应用所在的主机名 -->
<filter>
<filter-name>CAS Validation Filter</filter-name>
<filter-class>
org.jasig.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter
</filter-class>
<init-param>
<param-name>casServerUrlPrefix</param-name>
<param-value>https://172.18.113.78:8443/CasServer</param-value>
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://127.0.0.1:8080</param-value>
</init-param>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CAS Validation Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
如上配置中指定使用HTTPS协议，生成证书时指定的名称为上图中的172.18.113.78,访问后出错，结果如下：
严重: Servlet.service() for servlet [jsp] in context with path [/uum] threw exception java.lang.RuntimeException: javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No subject alternative names present at org.jasig.cas.client.util.CommonUtils.getResponseFromServer(CommonUtils.java:341) at org.jasig.cas.client.util.CommonUtils.getResponseFromServer(CommonUtils.java:305) at org.jasig.cas.client.validation.AbstractCasProtocolUrlBasedTicketValidator.retrieveResponseFromServer(AbstractCasProtocolUrlBasedTicketValidator.java:50) at org.jasig.cas.client.validation.AbstractUrlBasedTicketValidator.validate(AbstractUrlBasedTicketValidator.java:207) at org.jasig.cas.client.validation.AbstractTicketValidationFilter.doFilter(AbstractTicketValidationFilter.java:169) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.jasig.cas.client.authentication.AuthenticationFilter.doFilter(AuthenticationFilter.java:116) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.jasig.cas.client.session.SingleSignOutFilter.doFilter(SingleSignOutFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at fi.common.filter.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:125) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:619) Caused by: javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No subject alternative names present at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Alerts.java:174) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1591) at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:187) at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Handshaker.java:181) at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1035) at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:124) at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Handshaker.java:516) at com.sun.net.ssl.internal.ssl.Handshaker.process_record(Handshaker.java:454) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:884) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1096) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1123) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1107) at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:415) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:166) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1026) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234) at org.jasig.cas.client.util.CommonUtils.getResponseFromServer(CommonUtils.java:328) ... 30 more Caused by: java.security.cert.CertificateException: No subject alternative names present at sun.security.util.HostnameChecker.matchIP(HostnameChecker.java:142) at sun.security.util.HostnameChecker.match(HostnameChecker.java:75) at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkIdentity(X509TrustManagerImpl.java:264) at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:250) at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1014) ... 42 more
情景二：
生成证书时指定名称为域名（测试用的，修改了本地host文件）
例子同情景一中的例子，只是把web.xml中的IP地址改为了域名，测试结果为通过。
如果客户端访问出现如下错误：
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target这种错误往往是证书路径不对导致的。
可能原因一：tomcat使用的jdk和证书导入的jdk不是同一个
可能原因二：导入完成后需要重启（静态导入），重启一次不行建议重启第二次
可能原因三：jdk中的证书导入错误
结论
所以得出结论，生成证书时需要指定域名而非用IP地址。