diff --git a/library/x509_crt.c b/library/x509_crt.c
index cf62532..8775bcb 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -58,6 +58,10 @@
 
 #if defined(MBEDTLS_HAVE_TIME)
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
+#define WIN32_LEAN_AND_MEAN
+#ifndef _WIN32_WINNT
+#define _WIN32_WINNT 0x0600
+#endif
 #include <windows.h>
 #else
 #include <time.h>
@@ -2524,6 +2528,61 @@
     }
 }
 
+#ifdef _WIN32
+#ifdef _MSC_VER
+#pragma comment(lib, "ws2_32.lib")
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#elif (defined(__MINGW32__) || defined(__MINGW64__)) && _WIN32_WINNT >= 0x0600
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#endif
+#elif defined(__sun)
+/* Solaris requires -lsocket -lnsl for inet_pton() */
+#elif defined(__has_include)
+#if __has_include(<sys/socket.h>)
+#include <sys/socket.h>
+#endif
+#if __has_include(<arpa/inet.h>)
+#include <arpa/inet.h>
+#endif
+#endif
+
+/* Use whether or not AF_INET6 is defined to indicate whether or not to use
+ * the platform inet_pton() or a local implementation (below).  The local
+ * implementation may be used even in cases where the platform provides
+ * inet_pton(), e.g. when there are different includes required and/or the
+ * platform implementation requires dependencies on additional libraries.
+ * Specifically, Windows requires custom includes and additional link
+ * dependencies, and Solaris requires additional link dependencies.
+ * Also, as a coarse heuristic, use the local implementation if the compiler
+ * does not support __has_include(), or if the definition of AF_INET6 is not
+ * provided by headers included (or not) via __has_include() above. */
+#ifndef AF_INET6
+
+#define x509_cn_inet_pton(cn, dst) (0)
+
+#else
+
+static int x509_inet_pton_ipv6(const char *src, void *dst)
+{
+    return inet_pton(AF_INET6, src, dst) == 1 ? 0 : -1;
+}
+
+static int x509_inet_pton_ipv4(const char *src, void *dst)
+{
+    return inet_pton(AF_INET, src, dst) == 1 ? 0 : -1;
+}
+
+#endif /* AF_INET6 */
+
+static size_t x509_cn_inet_pton(const char *cn, void *dst)
+{
+    return strchr(cn, ':') == NULL
+            ? x509_inet_pton_ipv4(cn, dst) == 0 ? 4 : 0
+            : x509_inet_pton_ipv6(cn, dst) == 0 ? 16 : 0;
+}
+
 /*
  * Check for CN match
  */
@@ -2544,24 +2603,51 @@
     return -1;
 }
 
+static int x509_crt_check_san_ip(const mbedtls_x509_sequence *san,
+                                 const char *cn, size_t cn_len)
+{
+    uint32_t ip[4];
+    cn_len = x509_cn_inet_pton(cn, ip);
+    if (cn_len == 0) {
+        return -1;
+    }
+
+    for (const mbedtls_x509_sequence *cur = san; cur != NULL; cur = cur->next) {
+        const unsigned char san_type = (unsigned char) cur->buf.tag &
+                                       MBEDTLS_ASN1_TAG_VALUE_MASK;
+        if (san_type == MBEDTLS_X509_SAN_IP_ADDRESS &&
+            cur->buf.len == cn_len && memcmp(cur->buf.p, ip, cn_len) == 0) {
+            return 0;
+        }
+    }
+
+    return -1;
+}
+
 /*
  * Check for SAN match, see RFC 5280 Section 4.2.1.6
  */
-static int x509_crt_check_san(const mbedtls_x509_buf *name,
+static int x509_crt_check_san(const mbedtls_x509_sequence *san,
                               const char *cn, size_t cn_len)
 {
-    const unsigned char san_type = (unsigned char) name->tag &
-                                   MBEDTLS_ASN1_TAG_VALUE_MASK;
-
-    /* dNSName */
-    if (san_type == MBEDTLS_X509_SAN_DNS_NAME) {
-        return x509_crt_check_cn(name, cn, cn_len);
+    int san_ip = 0;
+    for (const mbedtls_x509_sequence *cur = san; cur != NULL; cur = cur->next) {
+        switch ((unsigned char) cur->buf.tag & MBEDTLS_ASN1_TAG_VALUE_MASK) {
+            case MBEDTLS_X509_SAN_DNS_NAME:                /* dNSName */
+                if (x509_crt_check_cn(&cur->buf, cn, cn_len) == 0) {
+                    return 0;
+                }
+                break;
+            case MBEDTLS_X509_SAN_IP_ADDRESS:              /* iPAddress */
+                san_ip = 1;
+                break;
+            /* (We may handle other types here later.) */
+            default: /* Unrecognized type */
+                break;
+        }
     }
 
-    /* (We may handle other types here later.) */
-
-    /* Unrecognized type */
-    return -1;
+    return san_ip ? x509_crt_check_san_ip(san, cn, cn_len) : -1;
 }
 
 /*
@@ -2572,31 +2658,23 @@
                                  uint32_t *flags)
 {
     const mbedtls_x509_name *name;
-    const mbedtls_x509_sequence *cur;
     size_t cn_len = strlen(cn);
 
     if (crt->ext_types & MBEDTLS_X509_EXT_SUBJECT_ALT_NAME) {
-        for (cur = &crt->subject_alt_names; cur != NULL; cur = cur->next) {
-            if (x509_crt_check_san(&cur->buf, cn, cn_len) == 0) {
-                break;
-            }
-        }
-
-        if (cur == NULL) {
-            *flags |= MBEDTLS_X509_BADCERT_CN_MISMATCH;
+        if (x509_crt_check_san(&crt->subject_alt_names, cn, cn_len) == 0) {
+            return;
         }
     } else {
         for (name = &crt->subject; name != NULL; name = name->next) {
             if (MBEDTLS_OID_CMP(MBEDTLS_OID_AT_CN, &name->oid) == 0 &&
                 x509_crt_check_cn(&name->val, cn, cn_len) == 0) {
-                break;
+                return;
             }
         }
 
-        if (name == NULL) {
-            *flags |= MBEDTLS_X509_BADCERT_CN_MISMATCH;
-        }
     }
+
+    *flags |= MBEDTLS_X509_BADCERT_CN_MISMATCH;
 }
 
 /*