diff --git a/pombola/middleware.py b/pombola/middleware.py
index 38127ecc5..f348c99b5 100644
--- a/pombola/middleware.py
+++ b/pombola/middleware.py
@@ -1,4 +1,6 @@
 from instances.models import Instance
+import socket
+from django.utils.deprecation import MiddlewareMixin
 
 class FakeInstanceMiddleware:
     """
@@ -12,3 +14,10 @@ def process_request(self, request):
         # speeches to any users of the site at the moment, so force
         # that no user of the site is regarded as its owner.
         request.is_user_instance = False
+
+# Which server behind load balancer served the request
+class AddServerDetailsMiddleware(MiddlewareMixin):
+    def process_response(self, request, response):
+        server_hostname = socket.gethostname()
+        response['X-Server'] = server_hostname
+        return response
diff --git a/pombola/settings/base.py b/pombola/settings/base.py
index 203f08254..d2bf04d32 100644
--- a/pombola/settings/base.py
+++ b/pombola/settings/base.py
@@ -228,6 +228,7 @@
     "pagination.middleware.PaginationMiddleware",
     "mapit.middleware.ViewExceptionMiddleware",
     "django.middleware.security.SecurityMiddleware",
+    "pombola.middleware.AddServerDetailsMiddleware",
 )
 
 CORS_ALLOW_HEADERS = default_headers + ("HTTP_AUTHORIZATION", "SENTRY-TRACE")