diff --git a/flask/helpers.py b/flask/helpers.py
index c6c2cddc..cfc2d408 100644
--- a/flask/helpers.py
+++ b/flask/helpers.py
@@ -958,3 +958,25 @@ def total_seconds(td):
     :rtype: int
     """
     return td.days * 60 * 60 * 24 + td.seconds
+
+def is_IP(string):
+    ipv4 = string.split('.')
+    ipv6 = string.split(':')
+    try:
+        for i,t in enumerate(ipv6):
+            if not t:
+                ipv6[i] = "0"
+        if(all(int(t,16) >= 0 and int(t,16) <= 65535 for t in ipv6)):
+            print("IPv6 address introduced in SESSION_COOKIE_DOMAIN!")
+            return True
+    except ValueError:
+        pass
+
+    if len(ipv4) == 4:
+        try:
+            if(all(int(t) >= 0 and int(t) <= 255 for t in ipv4)):
+                print("IPv4 address introduced in SESSION_COOKIE_DOMAIN!")
+        except ValueError:
+            return False
+    else:
+        return False
diff --git a/flask/sessions.py b/flask/sessions.py
index 4d67658a..86283f25 100644
--- a/flask/sessions.py
+++ b/flask/sessions.py
@@ -17,7 +17,7 @@ from werkzeug.http import http_date, parse_date
 from werkzeug.datastructures import CallbackDict
 from . import Markup, json
 from ._compat import iteritems, text_type
-from .helpers import total_seconds
+from .helpers import total_seconds, is_IP
 
 from itsdangerous import URLSafeTimedSerializer, BadSignature
 
@@ -332,6 +332,7 @@ class SecureCookieSessionInterface(SessionInterface):
 
     def save_session(self, app, session, response):
         domain = self.get_cookie_domain(app)
+        is_IP(domain)
         path = self.get_cookie_path(app)
 
         # Delete case.  If there is no session we bail early.