diff --git a/src/isinetaddr.c b/src/isinetaddr.c
index 473a3a5..05a75fd 100644
--- a/src/isinetaddr.c
+++ b/src/isinetaddr.c
@@ -4,8 +4,8 @@
 #include <isinetaddr.h>
 #include <errno.h>
 
-static
-int inrange(char buf[4])
+static int
+inrange(char buf[4])
 {
   char *err;
   long r;
@@ -20,7 +20,6 @@ isinetaddr(const char *str)
   char buf[4];
   int i = 0, j = 0, k = 0;
   size_t len = (str == NULL ? 0 : strnlen(str, 16));
-
   for (size_t l = 0; l < len; l++) {
     if (str[l] == '.') {
       if (inrange(buf)) {
@@ -43,6 +42,6 @@ isinetaddr(const char *str)
       return 0;
     }
   }
-  return j == 3 && i <= 12 ? 1 : 0;
+  return j == 3 && i <= 12 && inrange(buf);
 }
 
diff --git a/test/isinetaddr_test.c b/test/isinetaddr_test.c
index bfda3a1..9c60c83 100644
--- a/test/isinetaddr_test.c
+++ b/test/isinetaddr_test.c
@@ -7,10 +7,12 @@ const char *valid[] = {
   "192.168.1.1",
   "0.0.0.0",
   "255.255.255.255",
-  "123.45.67.89"
+  "123.45.67.89",
+  "123.45.67.255",
 };
 
 const char *invalid[] = {
+  "123.45.67.891",
   "192.168.500.1",
   ".192.168.1.1",
   "192..168.1.1",