diff --git a/gemini.py b/gemini.py
index 1216ee2..1c11270 100644
--- a/gemini.py
+++ b/gemini.py
@@ -3,6 +3,7 @@ import ssl
 import urllib.parse
 
 # See https://tildegit.org/solderpunk/gemini-demo-1/src/branch/master/gemini-demo.py
+# See also https://gemini.circumlunar.space/docs/specification.html for more details
 
 class Request():
     def __init__(self, url):
@@ -16,22 +17,33 @@ class Request():
 
     def makeRequest(self):
         try:
+            # Create socket
             s = socket.create_connection((self.hostname, self.port))
             context = ssl.SSLContext()
             context.check_hostname = False
             context.verify_mode = ssl.CERT_NONE
             s = context.wrap_socket(s, server_hostname = self.hostname)
+            # Send request
             s.sendall((self.url + '\r\n').encode("UTF-8"))
+
+            # Receive the answer
             fp = s.makefile("rb")
-            header = fp.readline().decode("UTF-8").strip()
-            status, mime = header.split()
-    
-            print("STATUS : " + status)
-            print("MIME   : " + mime)
-    
-            body = fp.read().decode("UTF-8")
-    
-            return body
+
+            # Read header
+            self.header = fp.readline().decode("UTF-8").strip()
+            self.status = self.header[0:2]
+            self.meta = self.header[3:]
+
+            # Handle errors
+            if self.status[0] == "4" or self.status[0] == "5":
+                # There is an error and no content so we display error code and error message
+                self.content = "Error " + self.status + " : " + self.meta
+            else:
+                # Read the content
+                self.content = fp.read().decode("UTF-8")
+
+            # Return the status code
+            return self.status
     
         except Exception as err:
             print(err)
diff --git a/main.py b/main.py
index ac09efb..681ffa3 100644
--- a/main.py
+++ b/main.py
@@ -1,4 +1,6 @@
 import tkinter as tk
+import tkinter.messagebox
+import tkinter.simpledialog
 import gemini
 
 # See https://tildegit.org/solderpunk/gemini-demo-1/src/branch/master/gemini-demo.py
@@ -12,10 +14,31 @@ class Application():
         self.current_URL = "about:home"
 
     def updateContent(self):
+        # Get url asked
         self.current_URL = self.nav_bar.getURL()
+
+        # New request
         r = gemini.Request(self.current_URL)
-        text = r.makeRequest()
-        self.content.setContent(text)
+        status = r.makeRequest()
+
+        # The server asked for user input
+        if status[0] == "1":
+            user_input = tkinter.simpledialog.askstring("User input", "The server asked for " + r.meta + ".")
+            self.nav_bar.URL_var.set(self.current_URL + "?" + user_input)
+            self.updateContent()
+        # If server asked for redirection
+        elif status[0] == "3":
+            # Ask to user
+            confirm = tkinter.messagebox.askyesno("Server redirection", "This server ask for redirection to " + r.meta + ". Follow ?")
+            # If he accepted
+            if confirm:
+                self.nav_bar.URL_var.set(r.meta)
+                self.updateContent()
+        # The server asked for client certificate, unsupported
+        elif status[0] == "6":
+            tkinter.messagebox.showerror("Client certificate required", "Error " + status + " : " + r.meta)
+        else:
+            self.content.setContent(r.content)
 
 class NavBar():
     def __init__(self, parent):