IP-Filter throws NPE

org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [default] in context with path [/site] threw exception java.lang.NullPointerException at org.onehippo.forge.ipfilter.common.BaseIpFilter.isIgnored(BaseIpFilter.java:232) at org.onehippo.forge.ipfilter.common.BaseIpFilter.allowed(BaseIpFilter.java:153) at org.onehippo.forge.ipfilter.common.BaseIpFilter.doFilter(BaseIpFilter.java:132) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176) at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:146) at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:91) at org.onehippo.forge.rewriting.HippoRewriteFilter.doFilter(HippoRewriteFilter.java:237) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:502) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1132) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1539) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1495) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748)