diff --git a/lib/dns.js b/lib/dns.js
index 04cc58755142ce..0796c880b00b65 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -1,6 +1,5 @@
 'use strict';
 
-const net = require('net');
 const util = require('util');
 
 const cares = process.binding('cares_wrap');
@@ -11,7 +10,7 @@ const GetAddrInfoReqWrap = cares.GetAddrInfoReqWrap;
 const GetNameInfoReqWrap = cares.GetNameInfoReqWrap;
 const QueryReqWrap = cares.QueryReqWrap;
 
-const isIp = net.isIP;
+const isIp = cares.isIP;
 const isLegalPort = internalNet.isLegalPort;
 
 
@@ -25,7 +24,7 @@ function errnoException(err, syscall, hostname) {
   }
   var ex = null;
   if (typeof err === 'string') {  // c-ares error code.
-    ex = new Error(syscall + ' ' + err + (hostname ? ' ' + hostname : ''));
+    ex = new Error(`${syscall} ${err} ${(hostname ? ' ' + hostname : '')}`);
     ex.code = err;
     ex.errno = err;
     ex.syscall = syscall;
@@ -38,7 +37,6 @@ function errnoException(err, syscall, hostname) {
   return ex;
 }
 
-
 // c-ares invokes a callback either synchronously or asynchronously,
 // but the dns API should always invoke a callback asynchronously.
 //
@@ -66,8 +64,9 @@ function makeAsync(callback) {
     } else {
       var args = new Array(arguments.length + 1);
       args[0] = callback;
-      for (var i = 1, a = 0; a < arguments.length; ++i, ++a)
+      for (var i = 1, a = 0; a < arguments.length; ++i, ++a) {
         args[i] = arguments[a];
+      }
       process.nextTick.apply(null, args);
     }
   };
@@ -76,8 +75,10 @@ function makeAsync(callback) {
 
 function onlookup(err, addresses) {
   if (err) {
-    return this.callback(errnoException(err, 'getaddrinfo', this.hostname));
+    this.callback(errnoException(err, 'getaddrinfo', this.hostname));
+    return;
   }
+
   if (this.family) {
     this.callback(null, addresses[0], this.family);
   } else {
@@ -87,16 +88,18 @@ function onlookup(err, addresses) {
 
 
 function onlookupall(err, addresses) {
-  var results = [];
   if (err) {
-    return this.callback(errnoException(err, 'getaddrinfo', this.hostname));
+    this.callback(errnoException(err, 'getaddrinfo', this.hostname));
+    return;
   }
 
+  const results = new Array(addresses.length);
+
   for (var i = 0; i < addresses.length; i++) {
-    results.push({
+    results[i] = {
       address: addresses[i],
       family: this.family || (addresses[i].indexOf(':') >= 0 ? 6 : 4)
-    });
+    };
   }
 
   this.callback(null, results);
@@ -134,8 +137,10 @@ exports.lookup = function lookup(hostname, options, callback) {
     family = options >>> 0;
   }
 
-  if (family !== 0 && family !== 4 && family !== 6)
-    throw new TypeError('Invalid argument: family must be 4 or 6');
+  if (family !== 0 && family !== 4 && family !== 6) {
+    const msg = `Invalid argument: family must be 4 or 6, got ${family}`;
+    throw new TypeError(msg);
+  }
 
   callback = makeAsync(callback);
 
@@ -148,7 +153,7 @@ exports.lookup = function lookup(hostname, options, callback) {
     return {};
   }
 
-  var matchedFamily = net.isIP(hostname);
+  var matchedFamily = isIP(hostname);
   if (matchedFamily) {
     if (all) {
       callback(null, [{address: hostname, family: matchedFamily}]);
@@ -176,8 +181,10 @@ exports.lookup = function lookup(hostname, options, callback) {
 
 
 function onlookupservice(err, host, service) {
-  if (err)
-    return this.callback(errnoException(err, 'getnameinfo', this.host));
+  if (err) {
+    this.callback(errnoException(err, 'getnameinfo', this.host));
+    return;
+  }
 
   this.callback(null, host, service);
 }
@@ -185,16 +192,19 @@ function onlookupservice(err, host, service) {
 
 // lookupService(address, port, callback)
 exports.lookupService = function(host, port, callback) {
-  if (arguments.length !== 3)
-    throw new Error('Invalid arguments');
+  if (arguments.length !== 3) {
+    throw new TypeError(`Expected 3 arguments, got ${arguments.length}`);
+  }
 
-  if (cares.isIP(host) === 0)
+  if (isIP(host) === 0) {
     throw new TypeError('"host" argument needs to be a valid IP address');
+  }
 
-  if (port == null || !isLegalPort(port))
+  if (port == null || !isLegalPort(port)) {
     throw new TypeError(`"port" should be >= 0 and < 65536, got "${port}"`);
+  }
 
-  port = +port;
+  port = Number(port);
   callback = makeAsync(callback);
 
   var req = new GetNameInfoReqWrap();
@@ -204,7 +214,9 @@ exports.lookupService = function(host, port, callback) {
   req.oncomplete = onlookupservice;
 
   var err = cares.getnameinfo(req, host, port);
-  if (err) throw errnoException(err, 'getnameinfo', host);
+  if (err) { 
+    throw errnoException(err, 'getnameinfo', host);
+  }
 
   callback.immediately = true;
   return req;
@@ -212,10 +224,11 @@ exports.lookupService = function(host, port, callback) {
 
 
 function onresolve(err, result) {
-  if (err)
+  if (err) {
     this.callback(errnoException(err, this.bindingName, this.hostname));
-  else
+  } else {
     this.callback(null, result);
+  }
 }
 
 
@@ -224,9 +237,10 @@ function resolver(bindingName) {
 
   return function query(name, callback) {
     if (typeof name !== 'string') {
-      throw new Error('"name" argument must be a string');
+      const msg = `"name" argument must be a string, got ${typeof name}`;
+      throw new TypeError(msg);
     } else if (typeof callback !== 'function') {
-      throw new Error('"callback" argument must be a function');
+      throw new TypeError('"callback" argument must be a function');
     }
 
     callback = makeAsync(callback);
@@ -236,14 +250,17 @@ function resolver(bindingName) {
     req.hostname = name;
     req.oncomplete = onresolve;
     var err = binding(req, name);
-    if (err) throw errnoException(err, bindingName);
+    if (err) {
+      throw errnoException(err, bindingName);
+    }
+
     callback.immediately = true;
     return req;
   };
 }
 
 
-var resolveMap = {};
+var resolveMap = Object.create(null);
 exports.resolve4 = resolveMap.A = resolver('queryA');
 exports.resolve6 = resolveMap.AAAA = resolver('queryAaaa');
 exports.resolveCname = resolveMap.CNAME = resolver('queryCname');
@@ -257,7 +274,7 @@ exports.resolveSoa = resolveMap.SOA = resolver('querySoa');
 exports.reverse = resolver('getHostByAddr');
 
 
-exports.resolve = function(hostname, type_, callback_) {
+exports.resolve = (hostname, type_, callback_) => {
   var resolver, callback;
   if (typeof type_ === 'string') {
     resolver = resolveMap[type_];
@@ -272,12 +289,12 @@ exports.resolve = function(hostname, type_, callback_) {
   if (typeof resolver === 'function') {
     return resolver(hostname, callback);
   } else {
-    throw new Error('Unknown type "' + type_ + '"');
+    throw new Error(`Unknown type ${type_}`);
   }
 };
 
 
-exports.getServers = function() {
+exports.getServers = () => {
   return cares.getServers();
 };
 
@@ -285,43 +302,42 @@ exports.getServers = function() {
 exports.setServers = function(servers) {
   // cache the original servers because in the event of an error setting the
   // servers cares won't have any servers available for resolution
-  var orig = cares.getServers();
+  var originalServers = cares.getServers();
 
-  var newSet = [];
+  const newSet = servers.map((serv) => {
+    var ipVersion = isIp(serv);
 
-  servers.forEach(function(serv) {
-    var ver = isIp(serv);
-
-    if (ver)
-      return newSet.push([ver, serv]);
-
-    var match = serv.match(/\[(.*)\](:\d+)?/);
+    if (ipVersion !== 0) {
+      return [ver, serv];
+    }
+    const match = serv.match(/\[(.*)\](:\d+)?/);
 
     // we have an IPv6 in brackets
     if (match) {
-      ver = isIp(match[1]);
-      if (ver)
-        return newSet.push([ver, match[1]]);
+      ipVersion = isIp(match[1]);
+      if (ipVersion !== 0) {
+        return [ver, match[1]];
+      }
     }
 
     var s = serv.split(/:\d+$/)[0];
-    ver = isIp(s);
+    ipVersion = isIp(s);
 
-    if (ver)
-      return newSet.push([ver, s]);
+    if (ipVersion !== 0) {
+      return [ver, s];
+    }
 
-    throw new Error('IP address is not properly formatted: ' + serv);
+    throw new Error(`IP address is not properly formatted: ${serv}`);
   });
 
-  var r = cares.setServers(newSet);
+  const errorNumber = cares.setServers(newSet);
 
-  if (r) {
+  if (errorNumber !== 0) {
     // reset the servers to the old servers, because ares probably unset them
-    cares.setServers(orig.join(','));
+    cares.setServers(originalServers.join(','));
 
     var err = cares.strerror(r);
-    throw new Error('c-ares failed to set servers: "' + err +
-                    '" [' + servers + ']');
+    throw new Error(`c-ares failed to set servers: ${err} [${servers}]`);
   }
 };