diff --git a/README.md b/README.md
index b1c0e44..490aa8e 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,8 @@ services:
       DB_USER: main
       DB_PASSWORD: your-db-password
       DB_NAME: main
+      DNS_SERVER: 10.1.1.2
+      DNS_SERVER_PORT: 5350
       WORKERS: 2 # number of workers to run (should be 2 * number of cores)
 
   db:
diff --git a/main.py b/main.py
index 6090787..775a7e4 100644
--- a/main.py
+++ b/main.py
@@ -7,6 +7,7 @@ import db
 import varo_auth
 import account
 import render
+import re
 
 app = Flask(__name__)
 dotenv.load_dotenv()
@@ -97,18 +98,15 @@ def add_link():
         return resp
 
     link=request.form['link']
-    url=request.form['url']
+    url=request.form['url'].lower()
 
     # Verify link is valid
     if not (url.startswith('http://') or url.startswith('https://')):
         url = 'https://' + url
 
-    try:
-        r = requests.get(url, timeout=5)
-        if r.status_code != 200:
-            return error('Invalid URL')
-    except:
-        return error('Invalid URL')
+    regexmatch = re.match(r"^^https?://([a-z0-9]+(-[a-z0-9]+)*\.)*([a-z0-9]+(-[a-z0-9]+)*)(/([a-z0-9.])+(-([a-z0-9.])+)?)*$", domain)
+    if not regexmatch:
+        return error('Invalid domain')
     
     if len(link) > 32:
         return error('Link too long')