diff --git a/README.md b/README.md
index d334fa4..bdc0380 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 [![Coverage Status](https://coveralls.io/repos/github/bcoe/which-cloud/badge.svg?branch=master)](https://coveralls.io/github/bcoe/which-cloud?branch=master)
 [![Standard Version](https://img.shields.io/badge/release-standard%20version-brightgreen.svg)](https://github.com/conventional-changelog/standard-version)
 
-given an IP address, return which cloud provider it belongs to (EC2, GCE, etc)
+given an ip address, return which cloud provider it belongs to (EC2, GCE, etc)
 
 ```sh
 > which-cloud 104.196.27.39
diff --git a/lib/which.js b/lib/which.js
new file mode 100644
index 0000000..5b767fd
--- /dev/null
+++ b/lib/which.js
@@ -0,0 +1,42 @@
+const parallel = require('async').parallel
+const ipRangeCheck = require('ip-range-check')
+const azure = require('./azure')
+const aws = require('./aws')
+
+module.exports = function (ip, done) {
+  var name = 'unknown'
+  parallel([
+    function (cb) {
+      check(ip, azure(), function (err, _name) {
+        if (err) return cb(err)
+        else {
+          if (_name) name = _name
+          return cb()
+        }
+      })
+    },
+    function (cb) {
+      check(ip, aws(), function (err, _name) {
+        if (err) return cb(err)
+        else {
+          if (_name) name = _name
+          return cb()
+        }
+      })
+    }
+  ], function (err) {
+    if (err) return done(err)
+    else return done(null, name)
+  })
+}
+
+function check (ip, cloud, cb) {
+  cloud.list(function (err, ranges) {
+    if (err) return cb(err)
+    else if (ipRangeCheck(ip, ranges)) {
+      return cb(null, cloud.name)
+    } else {
+      return cb()
+    }
+  })
+}
diff --git a/package.json b/package.json
index dcfee3a..aa87ac0 100644
--- a/package.json
+++ b/package.json
@@ -1,12 +1,12 @@
 {
   "name": "which-cloud",
   "version": "1.0.0",
-  "description": "given an IP address, return which cloud provider it belongs to (EC2, GCE, etc)",
+  "description": "given an ip address, return which cloud provider it belongs to (AWS, GCE, etc)",
   "main": "index.js",
   "global": true,
   "scripts": {
     "pretest": "standard",
-    "test": "nyc mocha test/*.js",
+    "test": "nyc mocha --timeout=2500 test/*.js",
     "coverage": "nyc report --reporter=text-lcov | coveralls",
     "release": "standard-version"
   },
diff --git a/test/aws.js b/test/aws.js
index 67f9f46..cec380d 100644
--- a/test/aws.js
+++ b/test/aws.js
@@ -1,13 +1,13 @@
-/* global describe, it */
+/* global describe, it, after */
 
 require('chai').should()
 
-var AWS = require('../lib/aws')
-var nock = require('nock')
+const AWS = require('../lib/aws')
+const nock = require('nock')
 
 describe('AWS', function () {
   it('returns a list of IP ranges for AWS', function (done) {
-    var aws = AWS()
+    const aws = AWS()
     aws.list(function (err, ranges) {
       if (err) return done(err)
       ranges.should.include('23.20.0.0/14')
@@ -16,8 +16,8 @@ describe('AWS', function () {
   })
 
   it('handles an upstream error', function (done) {
-    var aws = AWS()
-    var getRanges = nock('https://ip-ranges.amazonaws.com')
+    const aws = AWS()
+    const getRanges = nock('https://ip-ranges.amazonaws.com')
       .get('/ip-ranges.json')
       .reply(500)
     aws.list(function (err, ranges) {
@@ -26,4 +26,9 @@ describe('AWS', function () {
       return done()
     })
   })
+
+  after(function () {
+    nock.cleanAll()
+    nock.enableNetConnect()
+  })
 })
diff --git a/test/azure.js b/test/azure.js
index 406e159..71cd9c1 100644
--- a/test/azure.js
+++ b/test/azure.js
@@ -2,11 +2,11 @@
 
 require('chai').should()
 
-var Azure = require('../lib/azure')
+const Azure = require('../lib/azure')
 
 describe('Azure', function () {
   it('returns a list of IP ranges for Azure', function (done) {
-    var azure = Azure()
+    const azure = Azure()
     azure.list(function (err, ranges) {
       if (err) return done(err)
       ranges.should.include('40.112.124.0/24')
diff --git a/test/which.js b/test/which.js
new file mode 100644
index 0000000..1db63fb
--- /dev/null
+++ b/test/which.js
@@ -0,0 +1,31 @@
+/* global describe, it */
+
+require('chai').should()
+
+const which = require('../lib/which')
+
+describe('which', function () {
+  it('returns appropriate response for azure ip', function (done) {
+    which('94.245.97.0', function (err, name) {
+      if (err) return done(err)
+      name.should.equal('azure')
+      return done()
+    })
+  })
+
+  it('returns appropriate response for aws ip', function (done) {
+    which('54.173.231.160', function (err, name) {
+      if (err) return done(err)
+      name.should.equal('aws')
+      return done()
+    })
+  })
+
+  it("returns 'unknown' if ip is not recognized", function (done) {
+    which('9.9.9.9', function (err, name) {
+      if (err) return done(err)
+      name.should.equal('unknown')
+      return done()
+    })
+  })
+})