Index: src/main/java/org/apache/http/conn/util/InetAddressUtils.java IDEA additional info: Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP <+>UTF-8 =================================================================== --- src/main/java/org/apache/http/conn/util/InetAddressUtils.java (revision 1665411) +++ src/main/java/org/apache/http/conn/util/InetAddressUtils.java (revision ) @@ -43,7 +43,8 @@ } private static final String IPV4_BASIC_PATTERN_STRING = - "(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\\.){3}" + // initial 3 fields, 0-255 followed by . + "(([1-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\\.){1}" + // initial first field, 1-255 + "(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\\.){2}" + // following 2 fields, 0-255 followed by . "([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])"; // final field, 0-255 private static final Pattern IPV4_PATTERN = Index: src/test/java/org/apache/http/conn/util/TestInetAddressUtils.java IDEA additional info: Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP <+>UTF-8 =================================================================== --- src/test/java/org/apache/http/conn/util/TestInetAddressUtils.java (revision 1665411) +++ src/test/java/org/apache/http/conn/util/TestInetAddressUtils.java (revision ) @@ -48,6 +48,7 @@ Assert.assertFalse(InetAddressUtils.isIPv4Address("g.ar.ba.ge")); Assert.assertFalse(InetAddressUtils.isIPv4Address("192.168.0")); Assert.assertFalse(InetAddressUtils.isIPv4Address("256.255.255.255")); + Assert.assertFalse(InetAddressUtils.isIPv4Address("0.168.0.0")); //IP address that starts with zero not allowed } @Test