diff --git a/lib/structs.js b/lib/structs.js
index 807c975..005ed1f 100644
--- a/lib/structs.js
+++ b/lib/structs.js
@@ -429,10 +429,17 @@ function inet_ntop(buf) {
 function inet_pton(str) {
   var buf = new Buffer(16);
   buf.fill(0);
+  // IPv4-mapped IPv6.
+  if (str.indexOf("::ffff:") === 0) {
+    str = str.slice(7);
+  }
   // IPv4.
   if (str.indexOf(":") === -1) {
     IPv4_MAPPING.copy(buf);
-    var octets = str.split(/\./g).map(function(s) {return parseInt(s, 10);});
+    var octets = str.split(/\./g).map(function(o) {
+      assert(/^\d+$/.test(o), "Bad octet");
+      return parseInt(o, 10);
+    });
     // Support short form from inet_aton(3) man page.
     if (octets.length === 1) {
       buf.writeUInt32BE(octets[0], 12);
@@ -487,6 +494,8 @@ function inet_pton(str) {
       assert(groups.length === 8, "Bad IPv6 address");
     }
     for (i = 0; i < Math.min(groups.length, 8); i++) {
+      // Check against parseInt("127.0.0.1", 16) -> 295
+      assert(/^[0-9a-f]+$/.test(groups[i]), "Bad group");
       buf.writeUInt16BE(parseInt(groups[i], 16), i * 2);
     }
   }
diff --git a/tests/unit.js b/tests/unit.js
index 8cc20bb..0d5340f 100644
--- a/tests/unit.js
+++ b/tests/unit.js
@@ -346,6 +346,16 @@ describe("Common structures", function() {
       expect(net_addr.encode({short: true, services: ServicesBitfield().set(ServicesBitfield.NODE_NETWORK), host: "127.0.0.1", port: 8444}).toString("hex")).to.equal("000000000000000100000000000000000000ffff7f00000120fc");
       expect(net_addr.encode({short: true, host: "::1", port: 65000}).toString("hex")).to.equal("000000000000000100000000000000000000000000000001fde8");
     });
+
+    it("should encode IPv4-mapped IPv6", function() {
+      var encoded = net_addr.encode({host: "::ffff:127.0.0.1", port: 1234});
+      expect(net_addr.decode(encoded).host).to.equal("127.0.0.1");
+    });
+
+    it("should encode bad IPv4", function() {
+      var opts = {host: " 127.0.0.1", port: 1234};
+      expect(net_addr.encode.bind(null, opts)).to.throw(/bad octet/i);
+    });
   });
 
   describe("inv_vect", function() {