diff --git a/lib/adapters/http.js b/lib/adapters/http.js
index 9edf3fb8..1ea68785 100755
--- a/lib/adapters/http.js
+++ b/lib/adapters/http.js
@@ -19,6 +19,7 @@ var platform = require('../platform');
 var fromDataURI = require('../helpers/fromDataURI');
 var stream = require('stream');
 var estimateDataURLDecodedBytes = require('../helpers/estimateDataURLDecodedBytes.js');
+var shouldBypassProxy = require('../helpers/shouldBypassProxy');
 
 var isHttps = /https:?/;
 
@@ -46,9 +47,11 @@ function setProxy(options, configProxy, location) {
   if (!proxy && proxy !== false) {
     var proxyUrl = getProxyForUrl(location);
     if (proxyUrl) {
-      proxy = url.parse(proxyUrl);
-      // replace 'host' since the proxy object is not a URL object
-      proxy.host = proxy.hostname;
+      if (!shouldBypassProxy(location)) {
+        proxy = url.parse(proxyUrl);
+        // replace 'host' since the proxy object is not a URL object
+        proxy.host = proxy.hostname;
+      }
     }
   }
   if (proxy) {
@@ -273,7 +276,7 @@ module.exports = function httpAdapter(config) {
     } else {
       options.hostname = parsed.hostname;
       options.port = parsed.port;
-      setProxy(options, config.proxy, protocol + '//' + parsed.hostname + (parsed.port ? ':' + parsed.port : '') + options.path);
+      setProxy(options, config.proxy, protocol + '//' + parsed.host + options.path);
     }
 
     var transport;
diff --git a/lib/core/dispatchRequest.js b/lib/core/dispatchRequest.js
index 6ac7bc0e..37130312 100644
--- a/lib/core/dispatchRequest.js
+++ b/lib/core/dispatchRequest.js
@@ -6,6 +6,7 @@ var isCancel = require('../cancel/isCancel');
 var defaults = require('../defaults');
 var CanceledError = require('../cancel/CanceledError');
 var normalizeHeaderName = require('../helpers/normalizeHeaderName');
+var sanitizeHeaderValue = require('../helpers/sanitizeHeaderValue');
 
 /**
  * Throws a `CanceledError` if cancellation has been requested.
@@ -58,6 +59,10 @@ module.exports = function dispatchRequest(config) {
     }
   );
 
+  utils.forEach(config.headers, function sanitizeHeaderConfigValue(value, header) {
+    config.headers[header] = sanitizeHeaderValue(value);
+  });
+
   var adapter = config.adapter || defaults.adapter;
 
   return adapter(config).then(function onAdapterResolution(response) {
diff --git a/lib/helpers/sanitizeHeaderValue.js b/lib/helpers/sanitizeHeaderValue.js
new file mode 100644
index 00000000..fdef5d84
--- /dev/null
+++ b/lib/helpers/sanitizeHeaderValue.js
@@ -0,0 +1,22 @@
+'use strict';
+
+var utils = require('../utils');
+
+var INVALID_HEADER_VALUE_RE = /[^\x09\x20-\x7E\x80-\xFF]/g;
+var BOUNDARY_WHITESPACE_RE = /^[\x09\x20]|[\x09\x20]$/g;
+
+function sanitizeHeaderValue(value) {
+  if (value === false || value == null) {
+    return value;
+  }
+
+  if (utils.isArray(value)) {
+    return value.map(sanitizeHeaderValue);
+  }
+
+  return String(value)
+    .replace(INVALID_HEADER_VALUE_RE, '')
+    .replace(BOUNDARY_WHITESPACE_RE, '');
+}
+
+module.exports = sanitizeHeaderValue;
diff --git a/lib/helpers/shouldBypassProxy.js b/lib/helpers/shouldBypassProxy.js
new file mode 100644
index 00000000..92fef63d
--- /dev/null
+++ b/lib/helpers/shouldBypassProxy.js
@@ -0,0 +1,129 @@
+'use strict';
+
+var URL = require('url').URL;
+
+var DEFAULT_PORTS = {
+  http: 80,
+  https: 443,
+  ws: 80,
+  wss: 443,
+  ftp: 21
+};
+
+function parseNoProxyEntry(entry) {
+  var entryHost = entry;
+  var entryPort = 0;
+
+  if (entryHost.charAt(0) === '[') {
+    var bracketIndex = entryHost.indexOf(']');
+
+    if (bracketIndex !== -1) {
+      var host = entryHost.slice(1, bracketIndex);
+      var rest = entryHost.slice(bracketIndex + 1);
+
+      if (rest.charAt(0) === ':' && /^\d+$/.test(rest.slice(1))) {
+        entryPort = parseInt(rest.slice(1), 10);
+      }
+
+      return [host, entryPort];
+    }
+  }
+
+  var firstColon = entryHost.indexOf(':');
+  var lastColon = entryHost.lastIndexOf(':');
+
+  if (firstColon !== -1 && firstColon === lastColon && /^\d+$/.test(entryHost.slice(lastColon + 1))) {
+    entryPort = parseInt(entryHost.slice(lastColon + 1), 10);
+    entryHost = entryHost.slice(0, lastColon);
+  }
+
+  return [entryHost, entryPort];
+}
+
+function normalizeNoProxyHost(hostname) {
+  if (!hostname) {
+    return hostname;
+  }
+
+  if (hostname.charAt(0) === '[' && hostname.charAt(hostname.length - 1) === ']') {
+    hostname = hostname.slice(1, -1);
+  }
+
+  return hostname.replace(/\.+$/, '');
+}
+
+function isLoopbackIPv4(hostname) {
+  var octets = hostname.split('.');
+
+  if (octets.length !== 4) {
+    return false;
+  }
+
+  if (octets[0] !== '127') {
+    return false;
+  }
+
+  return octets.every(function testOctet(octet) {
+    return /^\d+$/.test(octet) && Number(octet) >= 0 && Number(octet) <= 255;
+  });
+}
+
+function isLoopbackHost(hostname) {
+  return hostname === 'localhost' || hostname === '::1' || isLoopbackIPv4(hostname);
+}
+
+module.exports = function shouldBypassProxy(location) {
+  var parsed;
+
+  try {
+    parsed = new URL(location);
+  } catch (err) {
+    return false;
+  }
+
+  var noProxy = (process.env.no_proxy || process.env.NO_PROXY || '').toLowerCase();
+
+  if (!noProxy) {
+    return false;
+  }
+
+  if (noProxy === '*') {
+    return true;
+  }
+
+  var protocol = parsed.protocol.split(':', 1)[0];
+  var port = parseInt(parsed.port, 10) || DEFAULT_PORTS[protocol] || 0;
+  var hostname = normalizeNoProxyHost(parsed.hostname.toLowerCase());
+
+  return noProxy.split(/[\s,]+/).some(function testNoProxyEntry(entry) {
+    if (!entry) {
+      return false;
+    }
+
+    var entryParts = parseNoProxyEntry(entry);
+    var entryHost = normalizeNoProxyHost(entryParts[0]);
+    var entryPort = entryParts[1];
+
+    if (!entryHost) {
+      return false;
+    }
+
+    if (entryPort && entryPort !== port) {
+      return false;
+    }
+
+    if (isLoopbackHost(hostname) && isLoopbackHost(entryHost)) {
+      return true;
+    }
+
+    if (entryHost.charAt(0) === '*') {
+      entryHost = entryHost.slice(1);
+    }
+
+    if (entryHost.charAt(0) === '.') {
+      return hostname.slice(-entryHost.length) === entryHost;
+    }
+
+    return hostname === entryHost;
+  });
+};
diff --git a/test/specs/headers.spec.js b/test/specs/headers.spec.js
index c1d10d7b..18b5d292 100644
--- a/test/specs/headers.spec.js
+++ b/test/specs/headers.spec.js
@@ -112,4 +112,17 @@ describe('headers', function () {
       done();
     });
   });
+
+  it('should sanitize headers containing invalid characters', function (done) {
+    axios('/foo', {
+      headers: {
+        'x-test': ' ok\r\nInjected: yes\t'
+      }
+    });
+
+    getAjaxRequest().then(function (request) {
+      testHeaderValue(request.requestHeaders, 'x-test', 'okInjected: yes');
+      done();
+    });
+  });
 });
diff --git a/test/unit/adapters/http.js b/test/unit/adapters/http.js
index ded712a4..c2c023fa 100644
--- a/test/unit/adapters/http.js
+++ b/test/unit/adapters/http.js
@@ -31,8 +31,39 @@ describe('supports http with nodejs', function () {
       proxy = null;
     }
     delete process.env.http_proxy;
+    delete process.env.HTTP_PROXY;
     delete process.env.https_proxy;
     delete process.env.no_proxy;
+    delete process.env.NO_PROXY;
+  });
+
+  it('should sanitize request headers containing invalid characters', function (done) {
+    server = http.createServer(function (req, res) {
+      res.setHeader('Content-Type', 'text/plain');
+      res.end(req.headers['x-test']);
+    }).listen(4444, function () {
+      axios.get('http://localhost:4444/', {
+        headers: {
+          'x-test': ' ok\r\nInjected: yes\t'
+        }
+      }).then(function (response) {
+        assert.equal(response.data, 'okInjected: yes');
+        done();
+      }).catch(done);
+    });
+  });
+
+  it('should preserve request error for unavailable host with invalid characters', function (done) {
+    axios.get('http://localhost:1/', {
+      headers: {
+        'x-test': 'ok\r\nInjected: yes'
+      }
+    }).then(function () {
+      done(new Error('request should not succeed'));
+    }).catch(function (error) {
+      assert.notEqual(error.message, 'Invalid character in header content ["x-test"]');
+      done();
+    });
   });
 
   it('should throw an error if the timeout property is not parsable as a number', function (done) {
@@ -967,6 +998,98 @@ describe('supports http with nodejs', function () {
     });
   });
 
+  it('should not use proxy for localhost with trailing dot when listed in no_proxy', function (done) {
+    var proxyRequests = 0;
+
+    proxy = http.createServer(function (request, response) {
+      proxyRequests += 1;
+      response.end('proxied');
+    }).listen(4000, function () {
+      process.env.http_proxy = 'http://localhost:4000/';
+      process.env.HTTP_PROXY = 'http://localhost:4000/';
+      process.env.no_proxy = 'localhost,127.0.0.1,::1';
+      process.env.NO_PROXY = 'localhost,127.0.0.1,::1';
+
+      axios.get('http://localhost.:1/', {
+        timeout: 100
+      }).then(function () {
+        done(new Error('request should not succeed'));
+      }).catch(function () {
+        assert.equal(proxyRequests, 0, 'should not use proxy for localhost with trailing dot');
+        done();
+      });
+    });
+  });
+
+  it('should not use proxy for bracketed IPv6 loopback when listed in no_proxy', function (done) {
+    var proxyRequests = 0;
+
+    proxy = http.createServer(function (request, response) {
+      proxyRequests += 1;
+      response.end('proxied');
+    }).listen(4000, function () {
+      process.env.http_proxy = 'http://localhost:4000/';
+      process.env.HTTP_PROXY = 'http://localhost:4000/';
+      process.env.no_proxy = 'localhost,127.0.0.1,::1';
+      process.env.NO_PROXY = 'localhost,127.0.0.1,::1';
+
+      axios.get('http://[::1]:1/', {
+        timeout: 100
+      }).then(function () {
+        done(new Error('request should not succeed'));
+      }).catch(function () {
+        assert.equal(proxyRequests, 0, 'should not use proxy for IPv6 loopback');
+        done();
+      });
+    });
+  });
+
+  it('should not use proxy for 127.0.0.1 when no_proxy is localhost', function (done) {
+    var proxyRequests = 0;
+
+    proxy = http.createServer(function (request, response) {
+      proxyRequests += 1;
+      response.end('proxied');
+    }).listen(4000, function () {
+      process.env.http_proxy = 'http://localhost:4000/';
+      process.env.HTTP_PROXY = 'http://localhost:4000/';
+      process.env.no_proxy = 'localhost';
+      process.env.NO_PROXY = 'localhost';
+
+      axios.get('http://127.0.0.1:1/', {
+        timeout: 100
+      }).then(function () {
+        done(new Error('request should not succeed'));
+      }).catch(function () {
+        assert.equal(proxyRequests, 0, 'should not use proxy for IPv4 loopback alias');
+        done();
+      });
+    });
+  });
+
+  it('should not use proxy for [::1] when no_proxy is localhost', function (done) {
+    var proxyRequests = 0;
+
+    proxy = http.createServer(function (request, response) {
+      proxyRequests += 1;
+      response.end('proxied');
+    }).listen(4000, function () {
+      process.env.http_proxy = 'http://localhost:4000/';
+      process.env.HTTP_PROXY = 'http://localhost:4000/';
+      process.env.no_proxy = 'localhost';
+      process.env.NO_PROXY = 'localhost';
+
+      axios.get('http://[::1]:1/', {
+        timeout: 100
+      }).then(function () {
+        done(new Error('request should not succeed'));
+      }).catch(function () {
+        assert.equal(proxyRequests, 0, 'should not use proxy for IPv6 loopback alias');
+        done();
+      });
+    });
+  });
+
   it('should use proxy for domains not in no_proxy', function (done) {
     server = http.createServer(function (req, res) {
       res.setHeader('Content-Type', 'text/html; charset=UTF-8');
diff --git a/test/unit/helpers/sanitizeHeaderValue.js b/test/unit/helpers/sanitizeHeaderValue.js
new file mode 100644
index 00000000..ae735a13
--- /dev/null
+++ b/test/unit/helpers/sanitizeHeaderValue.js
@@ -0,0 +1,20 @@
+var assert = require('assert');
+var sanitizeHeaderValue = require('../../../lib/helpers/sanitizeHeaderValue');
+
+describe('helpers::sanitizeHeaderValue', function () {
+  it('should remove invalid header characters', function () {
+    assert.strictEqual(sanitizeHeaderValue('ok\r\nInjected: yes'), 'okInjected: yes');
+    assert.strictEqual(sanitizeHeaderValue('ok\x01bad'), 'okbad');
+  });
+
+  it('should remove boundary whitespace', function () {
+    assert.strictEqual(sanitizeHeaderValue(' value\t'), 'value');
+  });
+
+  it('should sanitize array values recursively', function () {
+    assert.deepStrictEqual(
+      sanitizeHeaderValue([' safe=1 ', 'unsafe=1\nInjected: true']),
+      ['safe=1', 'unsafe=1Injected: true']
+    );
+  });
+});
diff --git a/test/unit/helpers/shouldBypassProxy.js b/test/unit/helpers/shouldBypassProxy.js
new file mode 100644
index 00000000..40e2839e
--- /dev/null
+++ b/test/unit/helpers/shouldBypassProxy.js
@@ -0,0 +1,74 @@
+var assert = require('assert');
+var shouldBypassProxy = require('../../../lib/helpers/shouldBypassProxy');
+
+var originalNoProxy = process.env.no_proxy;
+var originalNOProxy = process.env.NO_PROXY;
+
+function setNoProxy(value) {
+  process.env.no_proxy = value;
+  process.env.NO_PROXY = value;
+}
+
+describe('helpers::shouldBypassProxy', function () {
+  afterEach(function () {
+    if (originalNoProxy === undefined) {
+      delete process.env.no_proxy;
+    } else {
+      process.env.no_proxy = originalNoProxy;
+    }
+
+    if (originalNOProxy === undefined) {
+      delete process.env.NO_PROXY;
+    } else {
+      process.env.NO_PROXY = originalNOProxy;
+    }
+  });
+
+  it('should bypass proxy for localhost with a trailing dot', function () {
+    setNoProxy('localhost,127.0.0.1,::1');
+    assert.strictEqual(shouldBypassProxy('http://localhost.:8080/'), true);
+  });
+
+  it('should bypass proxy for bracketed ipv6 loopback', function () {
+    setNoProxy('localhost,127.0.0.1,::1');
+    assert.strictEqual(shouldBypassProxy('http://[::1]:8080/'), true);
+  });
+
+  it('should support bracketed ipv6 entries in no_proxy', function () {
+    setNoProxy('[::1]');
+    assert.strictEqual(shouldBypassProxy('http://[::1]:8080/'), true);
+  });
+
+  it('should match wildcard and explicit ports', function () {
+    setNoProxy('*.example.com,localhost:8080');
+
+    assert.strictEqual(shouldBypassProxy('http://api.example.com/'), true);
+    assert.strictEqual(shouldBypassProxy('http://localhost:8080/'), true);
+    assert.strictEqual(shouldBypassProxy('http://localhost:8081/'), false);
+  });
+
+  it('should treat localhost and loopback IP aliases as equivalent', function () {
+    setNoProxy('localhost');
+
+    assert.strictEqual(shouldBypassProxy('http://127.0.0.1:8080/'), true);
+    assert.strictEqual(shouldBypassProxy('http://[::1]:8080/'), true);
+
+    setNoProxy('127.0.0.1');
+
+    assert.strictEqual(shouldBypassProxy('http://localhost:8080/'), true);
+    assert.strictEqual(shouldBypassProxy('http://[::1]:8080/'), true);
+
+    setNoProxy('::1');
+
+    assert.strictEqual(shouldBypassProxy('http://localhost:8080/'), true);
+    assert.strictEqual(shouldBypassProxy('http://127.0.0.1:8080/'), true);
+  });
+
+  it('should keep loopback alias matching port-aware', function () {
+    setNoProxy('localhost:8080');
+
+    assert.strictEqual(shouldBypassProxy('http://127.0.0.1:8080/'), true);
+    assert.strictEqual(shouldBypassProxy('http://[::1]:8080/'), true);
+    assert.strictEqual(shouldBypassProxy('http://127.0.0.1:8081/'), false);
+  });
+});