diff --git a/rest_framework/throttling.py b/rest_framework/throttling.py
index 361dbddf06..0f10136d69 100644
--- a/rest_framework/throttling.py
+++ b/rest_framework/throttling.py
@@ -32,10 +32,10 @@ def get_ident(self, request):
             if num_proxies == 0 or xff is None:
                 return remote_addr
             addrs = xff.split(',')
-            client_addr = addrs[-min(num_proxies, len(xff))]
+            client_addr = addrs[-min(num_proxies, len(addrs))]
             return client_addr.strip()
 
-        return xff if xff else remote_addr
+        return ''.join(xff.split()) if xff else remote_addr
 
     def wait(self):
         """
@@ -173,12 +173,6 @@ def get_cache_key(self, request, view):
         if request.user.is_authenticated():
             return None  # Only throttle unauthenticated requests.
 
-        ident = request.META.get('HTTP_X_FORWARDED_FOR')
-        if ident is None:
-            ident = request.META.get('REMOTE_ADDR')
-        else:
-            ident = ''.join(ident.split())
-
         return self.cache_format % {
             'scope': self.scope,
             'ident': self.get_ident(request)