diff --git a/README.md b/README.md
index 9915ff9..b3ef98e 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,10 @@ This variable must be of the following format:
 
 `PROXY_DATA=server_names:test.com;www.test.com,port:80`
 
+Or written as regex:
+
+PROXY\_DATA=(KEY:VALUE,)\*KEY:VALUE
+
 The following options are possible:
 
 * **server_names**(required) the names of the virtual hosts separated by ";"
@@ -30,7 +34,7 @@ Run the container like this:
 
 That means that the container exposes all Web Apps on all IPs. Do **not** use the *ip* option from above on the target containers. The *PROXY_DATA* environment variables would be something like
 
-`PROXY_DATA=server_names:cooldomain.test.com,port:8080,location=/webApp`
+`PROXY_DATA=server_names:cooldomain.test.com,port:8080,location:/webApp`
 
 ### Multiple IPs
 This option is used if your Docker Host has multiple IPs (perhaps a public IP in the internet and a private IP on a VPN). It is possible to expose some Web Apps only to the private network.
@@ -41,6 +45,6 @@ One container must be started for each IP that should host Web Apps. For example
 
 If a target container does **not** have the *ip* option set, it listens on **all** IP adresses and will be handled by both containers.
 If a container uses, e.g.,  
-`PROXY_DATA=server_names:cooldomain.test.com,port:8080,location=/webApp,ip=10.1.2.3`
+`PROXY_DATA=server_names:cooldomain.test.com,port:8080,location:/webApp,ip:10.1.2.3`
 
 then it will be only available on the private 10.1.2.3 IP (perhaps using a VPN).
diff --git a/nginx_proxy.py b/nginx_proxy.py
index 5c95ca3..84de4b8 100755
--- a/nginx_proxy.py
+++ b/nginx_proxy.py
@@ -4,12 +4,13 @@ from docker import Client
 from docker.errors import APIError
 from string import Template
 import json
+import re
 import signal
 import os
 import logging
 
-target_path="/tmp/nginx/"
-pid_file="/var/run/nginx.pid"
+target_path = "/tmp/nginx/"
+pid_file = "/var/run/nginx.pid"
 non_location_template = """# proxy for container '$containername'
 server {
     listen $listen;
@@ -25,7 +26,7 @@ server {
 }
 """
 
-location_template="""# proxy for container '$containername'
+location_template = """# proxy for container '$containername'
 server {
     listen $listen;
     server_name $names;
@@ -43,21 +44,24 @@ server {
 }
 """
 
+
 def print_json(data):
     """Prints the given value in JSON to stdout. Use this for debugging only"""
     print(json.dumps(data, sort_keys=True, indent=4))
 
+
 def analyse_env_vars(inspect_data):
     """Extracts the environment variables from the given result of an 'inspect
         container' call."""
     env_data = {}
-    if not 'Env' in inspect_data['Config'] or inspect_data['Config']['Env'] is None:
+    if 'Env' not in inspect_data['Config'] or inspect_data['Config']['Env'] is None:
         return env_data
     for env_var in inspect_data['Config']['Env']:
         t = env_var.split("=")
         env_data[t[0]] = t[1]
     return env_data
 
+
 def analyse_proxy_data(data):
     """Extracts the data for the proxy configuration (envrionment variable
         'PROXY_DATA' and converts it to a dictionary."""
@@ -67,20 +71,33 @@ def analyse_proxy_data(data):
         proxy_data[t[0]] = t[1]
     return proxy_data
 
+
+def check_proxy_data_format(var_content):
+    """
+    Validates the content of the variable.
+    :param var_content: content of the proxy data variable
+    :return: True if the content is of valid format, False otherwise
+    """
+    return re.match(r"^(\w+:[^:,]+,)+\w+:[^:,]+$", var_content) is not None
+
+
 def extract_ip(inspect_data):
     """extracts the container's ip from the given inspect data"""
     return inspect_data['NetworkSettings']['IPAddress']
 
+
 def extract_name(inspect_data):
     """extracts the container's name from the given inspect data"""
     return inspect_data['Name']
 
-def get_if_available(dict, key, defValue):
-    if key in dict:
-        return dict[key]
+
+def get_if_available(dictionary, key, defValue):
+    if key in dictionary:
+        return dictionary[key]
     else:
         return defValue
 
+
 def handle_container(id):
     """This function take a container's id and collects all data required
         to create a proper proxy configuration. The configuration is then
@@ -88,6 +105,9 @@ def handle_container(id):
     inspect_data = client.inspect_container(id)
     env_vars = analyse_env_vars(inspect_data)
     if 'PROXY_DATA' in env_vars:
+        if not check_proxy_data_format(env_vars['PROXY_DATA']):
+            logging.info('cannot handle container with id "%s" named "%s": %s', id, extract_name(inspect_data), env_vars['PROXY_DATA'])
+            return
         proxy_data = analyse_proxy_data(env_vars)
         container_listen_ip = get_if_available(proxy_data, 'ip', '0.0.0.0')
         if container_listen_ip != '0.0.0.0' and container_listen_ip not in listen_ips:
@@ -111,15 +131,18 @@ def handle_container(id):
             else:
                 file.write(Template(location_template).substitute(substitutes))
 
+
 def reload_nginx_configuration():
     logging.info('HUPing nginx')
     os.kill(pid, signal.SIGHUP)
 
+
 def get_pid():
     """This function reads the process id from the given file."""
     with open(pid_file, 'r') as file:
         return int(file.read())
 
+
 def get_docker_id():
     """This function extracts the container's id from /proc/self/cgroup."""
     id = ''
@@ -138,6 +161,7 @@ def get_docker_id():
         logging.error('could not determine container\'s id!')
     return id
 
+
 def get_listen_ips():
     inspect_data = client.inspect_container(get_docker_id())
     mappings = inspect_data['NetworkSettings']['Ports']['80/tcp']
@@ -150,6 +174,7 @@ def get_listen_ips():
             ips.append(data['HostIp'])
     return ips
 
+
 def setup_logging():
     logging.basicConfig(format='%(asctime)s [%(levelname)s]: %(message)s', level=logging.INFO)