diff --git a/types/netmask/index.d.ts b/types/netmask/index.d.ts
index 10bc2f5c526781..b4bd9777a4f441 100644
--- a/types/netmask/index.d.ts
+++ b/types/netmask/index.d.ts
@@ -27,7 +27,7 @@ export class Netmask {
     /**
      * The blocks broadcast address (eg: 192.168.1.0/24 => 192.168.1.255)
      */
-    broadcast: string;
+    broadcast: string | undefined;
     /**
      * The number of IP addresses in a block (eg: 256).
      */
diff --git a/types/netmask/netmask-tests.ts b/types/netmask/netmask-tests.ts
index 475766dd8b4aae..e0d2a1a4444726 100644
--- a/types/netmask/netmask-tests.ts
+++ b/types/netmask/netmask-tests.ts
@@ -10,6 +10,11 @@ if (block.contains("10.0.8.10")) {
 block = new netmask.Netmask("216.240.32.0", "255.255.255.0");
 block = new netmask.Netmask("216.240.32.0", 24);
 
+block = new netmask.Netmask("216.240.32.0");
+if (typeof block.broadcast === undefined) {
+    console.log("no broadcast address for /32 block");
+}
+
 class CustomizedNetmask extends netmask.Netmask {
     // Test that we can override `next` to return a CustomizedNetmask (as opposed to netmask.Netmask) object
     next(count: number = 1): CustomizedNetmask {