diff --git a/netbox-scanner/nbscan.py b/netbox-scanner/nbscan.py
index 9a7b1ee..65afc17 100644
--- a/netbox-scanner/nbscan.py
+++ b/netbox-scanner/nbscan.py
@@ -26,6 +26,22 @@ class NetBoxScanner(object):
         self.stats = {'created':0, 'updated':0, 'deleted':0,
             'undiscovered':0, 'duplicated':0}
     
+    def parser(self, networks):
+        '''Parses a list of networks in CIDR notation.
+
+        :param networks: a list of networks like ['10.0.0.0/8',...]
+        :return: False if parsing is OK, or a string with duplicated
+        or mistyped networks.
+        '''
+        ipv4 = re.compile(r'^((2([0-4][0-9]|5[0-5])|1?[0-9]?[0-9])\.){3}(2([0-4][0-9]|5[0-5])|1?[0-9]?[0-9])\/(3[012]|[12]?[0-9])$')
+        duplicated = set([x for x in networks if networks.count(x)>1])
+        if duplicated:
+            return ', '.join(duplicated)
+        for net in networks:
+            if not re.match(ipv4, net):
+                return net
+        return False
+    
     def get_description(self, address, name, cpe):
         '''Define a description based on hostname and CPE'''
         if name:
@@ -73,7 +89,9 @@ class NetBoxScanner(object):
 
     def logger(self, logtype, **kwargs):
         '''Logs and updates stats for NetBox interactions.'''
-        if logtype == 'created':
+        if logtype == 'scanned':
+            logging.info('scanned: {} ({} hosts discovered)'.format(kwargs['net'], kwargs['hosts']))
+        elif logtype == 'created':
             logging.info('created: {}/32 "{}"'.format(kwargs['address'], 
                 kwargs['description']))
             self.stats['created'] += 1
@@ -92,7 +110,9 @@ class NetBoxScanner(object):
             self.stats['undiscovered'] += 1
         elif logtype == 'duplicated':
             logging.error('duplicated: {}/32'.format(kwargs['address']))
-            self.stats['duplicated'] += 1            
+            self.stats['duplicated'] += 1
+        elif logtype == 'mistyped':
+            logging.error('mistyped: {}'.format(kwargs['badnets']))
 
     def sync_host(self, host):
         '''Syncs a single host to NetBox.
@@ -122,14 +142,19 @@ class NetBoxScanner(object):
         '''Scan some networks and sync them to NetBox.
 
         :param networks: a list of valid networks, like ['10.0.0.0/8']
-        :return: synching statistics are returned as a tuple
+        :return: synching statistics
         '''
         for s in self.stats:
             self.stats[s] = 0
+        
+        parsing = self.parser(networks)
+        if parsing:
+            self.logger('mistyped', badnets=parsing)
+            return False
+
         for net in networks:
             hosts = self.scan(net)
-            logging.info('scan: {} ({} hosts discovered)'.format(net, 
-                len(hosts)))
+            self.logger('scanned', net=net, hosts=len(hosts))
             for host in hosts:
                 self.sync_host(host)
             
@@ -147,6 +172,5 @@ class NetBoxScanner(object):
                                 description=nbhost.description)
                     except (AttributeError, ValueError):
                         pass
-        return (self.stats['created'], self.stats['updated'], 
-            self.stats['deleted'], self.stats['undiscovered'], 
-            self.stats['duplicated'])
+
+        return True
diff --git a/netbox-scanner/netbox-scanner.py b/netbox-scanner/netbox-scanner.py
index 2316fdf..a9246a1 100644
--- a/netbox-scanner/netbox-scanner.py
+++ b/netbox-scanner/netbox-scanner.py
@@ -40,8 +40,9 @@ disable_warnings(InsecureRequestWarning)
 nbs = NetBoxScanner(args.address, args.token, args.verify, args.nmap, 
     args.devices, args.tag, args.unknown)
 logging.info('started: {} networks'.format(len(args.networks)))
-stats = nbs.sync(args.networks)
-logging.info('finished: +{} ~{} -{} ?{} !{}'.format(stats[0], stats[1], 
-    stats[2], stats[3], stats[4]))
+nbs.sync(args.networks)
+logging.info('finished: +{} ~{} -{} ?{} !{}'.format(nbs.stats['created'], 
+    nbs.stats['updated'], nbs.stats['deleted'], nbs.stats['undiscovered'], 
+    nbs.stats['duplicated']))
 
 exit(0)
diff --git a/setup.py b/setup.py
index 4c46037..fe505aa 100644
--- a/setup.py
+++ b/setup.py
@@ -7,7 +7,7 @@ with open('README.md', 'r') as fh:
 
 setuptools.setup(
     name='netbox-scanner',
-    version='0.5.2',
+    version='0.5.3',
     author='José Lopes de Oliveira Jr.',
     author_email='jlojunior@gmail.com',
     description='A scanner util for NetBox',