diff --git a/.gitmodules b/.gitmodules
index 1ac9b49..e69de29 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +0,0 @@
-[submodule "cymruwhois"]
-	path = cymruwhois
-	url = https://github.com/JustinAzoff/python-cymruwhois.git
diff --git a/MANIFEST.in b/MANIFEST.in
index b6c0f3f..427cfae 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,2 +1 @@
 include LICENSE README.md TODO.md public-servers.txt
-include cymruwhois/*.py
diff --git a/cymruwhois b/cymruwhois
deleted file mode 160000
index a345433..0000000
--- a/cymruwhois
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit a34543335cbef02b1b615e774ce5b6187afb0cc2
diff --git a/dnseval.py b/dnseval.py
index 892a036..d282e3b 100755
--- a/dnseval.py
+++ b/dnseval.py
@@ -40,7 +40,7 @@ import dns.resolver
 
 __author__ = 'Babak Farrokhi (babak@farrokhi.net)'
 __license__ = 'BSD'
-__version__ = "1.6.2"
+__version__ = "1.6.3"
 __progname__ = os.path.basename(sys.argv[0])
 shutdown = False
 
diff --git a/dnsping.py b/dnsping.py
index 6d075a7..eab8e75 100755
--- a/dnsping.py
+++ b/dnsping.py
@@ -40,7 +40,7 @@ import dns.resolver
 
 __author__ = 'Babak Farrokhi (babak@farrokhi.net)'
 __license__ = 'BSD'
-__version__ = "1.6.2"
+__version__ = "1.6.3"
 __progname__ = os.path.basename(sys.argv[0])
 shutdown = False
 
diff --git a/dnstraceroute.py b/dnstraceroute.py
index 4c66301..705585f 100755
--- a/dnstraceroute.py
+++ b/dnstraceroute.py
@@ -39,13 +39,20 @@ import dns.query
 import dns.rdatatype
 import dns.resolver
 
-from cymruwhois import cymruwhois
+import cymruwhois
 
+# Global Variables
 __author__ = 'Babak Farrokhi (babak@farrokhi.net)'
 __license__ = 'BSD'
-__version__ = "1.6.2"
+__version__ = "1.6.3"
 _ttl = None
 quiet = False
+whois_cache = {}
+shutdown = False
+
+# Constants
+__progname__ = os.path.basename(sys.argv[0])
+WHOIS_CACHE = 'whois.cache'
 
 
 class CustomSocket(socket.socket):
@@ -64,11 +71,6 @@ def test_import():
     pass
 
 
-# Constants
-__progname__ = os.path.basename(sys.argv[0])
-WHOIS_CACHE = 'whois.cache'
-
-
 class Colors(object):
     N = '\033[m'  # native
     R = '\033[31m'  # red
@@ -85,35 +87,41 @@ class Colors(object):
             self.B = ''
 
 
-# Globarl Variables
-shutdown = False
-
-
-def whoisrecord(ip):
+def whois_lookup(ip):
     try:
-        currenttime = time.perf_counter()
+        global whois_cache
+        currenttime = time.time()
         ts = currenttime
-        if ip in whois:
-            asn, ts = whois[ip]
+        if ip in whois_cache:
+            asn, ts = whois_cache[ip]
         else:
             ts = 0
         if (currenttime - ts) > 36000:
             c = cymruwhois.Client()
             asn = c.lookup(ip)
-            whois[ip] = (asn, currenttime)
+            whois_cache[ip] = (asn, currenttime)
         return asn
     except Exception as e:
         return e
 
 
-try:
-    pkl_file = open(WHOIS_CACHE, 'rb')
+def load_whois_cache(cachefile):
     try:
-        whois = pickle.load(pkl_file)
-    except EOFError:
+        pkl_file = open(cachefile, 'rb')
+        try:
+            whois = pickle.load(pkl_file)
+            pkl_file.close()
+        except Exception:
+            whois = {}
+    except IOError:
         whois = {}
-except IOError:
-    whois = {}
+    return whois
+
+
+def save_whois_cache(cachefile, whois_data):
+    pkl_file = open(cachefile, 'wb')
+    pickle.dump(whois_data, pkl_file)
+    pkl_file.close()
 
 
 def usage():
@@ -367,11 +375,11 @@ def main():
         if curr_addr:
             as_name = ""
             if as_lookup:
-                asn = whoisrecord(curr_addr)
+                asn = whois_lookup(curr_addr)
                 as_name = ''
                 try:
                     if asn and asn.asn != "NA":
-                        as_name = "[%s %s] " % (asn.asn, asn.owner)
+                        as_name = "[AS%s %s] " % (asn.asn, asn.owner)
                 except AttributeError:
                     if shutdown:
                         sys.exit(0)
@@ -404,7 +412,7 @@ def main():
 
 if __name__ == '__main__':
     try:
+        whois_cache = load_whois_cache(WHOIS_CACHE)
         main()
     finally:
-        pkl_file = open(WHOIS_CACHE, 'wb')
-        pickle.dump(whois, pkl_file)
+        save_whois_cache(WHOIS_CACHE, whois_cache)
diff --git a/requirements.txt b/requirements.txt
index fae5618..43b4b3f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1,2 @@
 dnspython>=1.15.0
+cymruwhois>=1.6
diff --git a/setup.py b/setup.py
index 9eb423a..3d5edab 100644
--- a/setup.py
+++ b/setup.py
@@ -2,10 +2,10 @@ from setuptools import setup, find_packages
 
 setup(
     name="dnsdiag",
-    version="1.6.2",
+    version="1.6.3",
     packages=find_packages(),
     scripts=["dnseval.py", "dnsping.py", "dnstraceroute.py"],
-    install_requires=['dnspython>=1.15.0'],
+    install_requires=['dnspython>=1.15.0', 'cymruwhois>=1.6'],
 
     classifiers=[
         "Topic :: System :: Networking",