diff --git a/src/lib.rs b/src/lib.rs
index e54707b..6221acb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -297,6 +297,12 @@ mod test {
         assert!(cidr.is_err());
     }
 
+    #[test]
+    fn parse_v4_non_zero_host_bits() {
+        let cidr = Ipv4Network::from_cidr("10.1.1.1/24");
+        assert!(cidr.is_err());
+    }
+
     #[test]
     fn parse_v4_fail_prefix() {
         let cidr = Ipv4Network::from_cidr("0/39");