diff --git a/netmask/netmask-tests.ts b/netmask/netmask-tests.ts
new file mode 100644
index 000000000..519e1722e
--- /dev/null
+++ b/netmask/netmask-tests.ts
@@ -0,0 +1,16 @@
+
+///<reference path="netmask.d.ts" />
+
+import netmask = require('netmask');
+
+var address: string = '127.0.0.1';
+
+var nm = new netmask.Netmask(address, '255.255.255.0');
+
+var nm2 = new netmask.Netmask('127.0.0.1/255.255.255.0');
+
+if (nm.contains('127.0.0.123')) {}
+
+nm.forEach((ip: string): void => console.log(ip));
+
+var adjacent: netmask.Netmask = nm.next();
diff --git a/netmask/netmask.d.ts b/netmask/netmask.d.ts
new file mode 100644
index 000000000..32afa25ae
--- /dev/null
+++ b/netmask/netmask.d.ts
@@ -0,0 +1,47 @@
+// Type definitions for Netmask 1.0.5
+// Project: https://github.com/rs/node-netmask
+// Definitions by: Matt Frantz <https://github.com/mhfrantz/>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+// netmask.d.ts
+
+declare module 'netmask' {
+
+  export function long2ip(long: number): string;
+  export function ip2long(ip: string): number;
+
+  export class Netmask {
+    maskLong: number;
+    bitmask: number;
+    netLong: number;
+    // The number of IP address in the block (eg.: 254)
+    size: number;
+    // The address of the network block as a string (eg.: 216.240.32.0)
+    base: string;
+    // The netmask as a string (eg.: 255.255.255.0)
+    mask: string;
+    // The host mask, the opposite of the netmask (eg.: 0.0.0.255)
+    hostmask: string;
+    // The first usable address of the block
+    first: string;
+    // The last  usable address of the block
+    last: string;
+    // The block's broadcast address: the last address of the block (eg.: 192.168.1.255)
+    broadcast: string;
+
+    constructor (netmask: string);
+    constructor (net: string, mask: string);
+
+    // Returns true if the given ip or netmask is contained in the block
+    contains(ip: string | Netmask | number): boolean;
+
+    // Returns the Netmask object for the block which follow this one
+    next(count?: number): Netmask;
+
+    // Evaluate a function on each IP address
+    forEach(fn: (ip: string, long: number, index: number) => void): void;
+
+    // Returns the complete netmask formatted as `base/bitmask`
+    toString(): string;
+  }
+}