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 d64d127..84de4b8 100755
--- a/nginx_proxy.py
+++ b/nginx_proxy.py
@@ -4,6 +4,7 @@ from docker import Client
 from docker.errors import APIError
 from string import Template
 import json
+import re
 import signal
 import os
 import logging
@@ -71,6 +72,15 @@ def analyse_proxy_data(data):
     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']
@@ -95,6 +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: