diff --git a/letsencrypt/client/validator.py b/letsencrypt/client/validator.py
index d7634a727..ea2a73a83 100644
--- a/letsencrypt/client/validator.py
+++ b/letsencrypt/client/validator.py
@@ -1,7 +1,15 @@
 """Validators to determine the current webserver configuration"""
+import subprocess
 import zope.interface
 import requests
+
 from letsencrypt.client import interfaces
+from subprocess import PIPE
+
+
+OCSP_OPENSSL_CMD = "openssl s_client -connect {hostname}:443 -tls1 -tlsextdebug -status"
+OCSP_OPENSSL_DELIMITER = "OCSP response:"
+OCSP_OPENSSL_NO_RESPONSE = "no response sent"
 
 
 class ValidationError(Exception):
@@ -15,41 +23,67 @@ class Validator(object):
         response = requests.get("http://" + name, allow_redirects=False)
 
         if response.status_code not in (301, 303):
-            raise ValidationError("Server did not respond with redirect code.")
-
-        if response.status_code != 301:
-            raise ValidationError("Server did not redirect with permanent code.")
+            return False
 
         redirect_location = response.headers.get("location", "")
         if not redirect_location.startswith("https://"):
-            raise ValidationError("Server did not redirect to HTTPS connection.")
+            return False
+
+        if response.status_code != 301:
+            raise ValidationError("Server did not redirect with permanent code.")
 
         return True
 
     def https(self, names):
         for name in names:
-            request.get("https://" + name, verify=True)
+            requests.get("https://" + name, verify=True)
         return True
 
     def hsts(self, name):
-        headers = requests.get("https://" + name, verify=False).headers
+        headers = requests.get("https://" + name).headers
         hsts_header = headers.get("strict-transport-security")
         
-        if not hsts_headers:
-            raise ValidationError("Server responed with either no or an empty HSTS header.")
+        if not hsts_header:
+            return False
 
         # Split directives following RFC6797, section 6.1
-        directives = [d.split("=") for d in hsts_headers.split(";")]
+        directives = [d.split("=") for d in hsts_header.split(";")]
         max_age = [d for d in directives if d[0] == "max-age"][0]
         
         try:
             max_age_name, max_age_value = max_age
             max_age_value = int(max_age_value)
         except ValueError:
-            raise ValidationError("Server responed with invalid HSTS header field.")
+            raise ValidationError("Server responded with invalid HSTS header field.")
 
         return True
 
-    def ocsp_stapling(self):
-        raise NotImplementedError("OCSP checking not yet implemented.")
+    def ocsp_stapling(self, name):
+        command = OCSP_OPENSSL_CMD.format(hostname=name).split(" ")
+        openssl = subprocess.Popen(command, stdin=PIPE, stdout=PIPE, stderr=PIPE)
+        stdout, stderr = openssl.communicate("QUIT\n")
+
+        if openssl.returncode != 0:
+            raise ValidationError("OpenSSL quit with error-code: {openssl.returncode}.".format(openssl=openssl))
+
+        ocsp_status = next(line for line in stdout.split("\n") if line.startswith(OCSP_OPENSSL_DELIMITER))
+        return OCSP_OPENSSL_NO_RESPONSE not in ocsp_status
+
+
+if __name__ == '__main__':
+    print("letsencrypt.org:")
+    print(Validator().ocsp_stapling("letsencrypt.org"))
+    print(Validator().hsts("letsencrypt.org"))
+    print(Validator().https(["letsencrypt.org"]))
+    print(Validator().redirect("letsencrypt.org"))
+    print(Validator().ocsp_stapling("letsencrypt.org"))
+
+    print("\ntweakers.net:")
+    print(Validator().hsts("tweakers.net"))
+    print(Validator().https(["tweakers.net"]))
+    print(Validator().redirect("tweakers.net"))
+    print(Validator().ocsp_stapling("tweakers.net"))
+
+    print("\nnon-existing-domain.net:")
+    print(Validator().ocsp_stapling("non-existing-domain.net"))