--- a/plugins/mod_s2s/mod_s2s.lua	Wed Jul 24 21:49:36 2013 +0200
+++ b/plugins/mod_s2s/mod_s2s.lua	Sun Aug 04 17:33:00 2013 +0200
@@ -255,6 +255,7 @@
 				else
 					session.cert_identity_status = "invalid"
 				end
+				(session.log or log)("debug", "certificate identity validation result: %s", session.cert_identity_status);
 			end
 		end
 	end